BE344464A - - Google Patents

Description

       

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  ASSOOIATED TELEPHONE AND TELEGRAPH COMPANY
The present invention relates to telephone systems and although some of its characteristics are capable of allowing a wider application, it is more particularly applicable to systems in which calls are established by means of automatic switches. which are directly activated by the subscriber calling at. by means of a dial switch.



   The object of the invention is more especially applicable in addition to systems of the type known under the designation of direct impulse systems in the

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 which one or more of the electromagnets serving to actuate the various switches receive their working current on conductors starting from the preceding switch. Hitherto, difficulties have been experienced in ensuring satisfactory operation with systems of this type owing to the fact that the currents required may be relatively large and also owing to the differences between the respective potentials of the earths at points situated apart. a certain distance from each other, for example in different central offices.

   The main object of the present invention is improved devices for overcoming these difficulties, so that the advantages which the direct pulse presents from other points of view can be fully realized.



   One of the characteristics of the object of the invention consists in using, in a system comprising automatic switches actuated step by step by means of electrical pulses, an electric motor supplied by a working current on a loop circuit. comprising two conductors in series from a preceding switch. another characteristic of the object of the invention is that the circuit for the motor electromagnet of a switch is closed when said switch is taken in service and the exciter of the switch is closed. electromagnet is then effected by increasing the current flowing through the circuit.



   Another characteristic of the object of the invention relates to the application of a translator

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 pulse in which the pulse responsive relay is connected to a circuit comprising the two incoming line conductors in series, and is set within certain limits, able to act only when the current flow is greater than that which passes when the switch is put into operation.



   Another characteristic of the object of the invention is still the application of a pulse response device, in which two relays of different sensitivity are coupled in series in a loop pulse circuit, so that the One of the relays can respond to a series of pulses with variations in circuit current, while the second relay remains energized for the duration of the series of pulses.



   For the sake of clarity a preferred embodiment of the object of the invention is described below with reference to the accompanying drawings. However, it must be understood that the device described is simply given by way of example and that various modifications could be made to it relating in particular to the details of the circuits without thereby departing from the scope of the invention.



   In the accompanying drawings, comprising FIGS. 1 to 12, figs. 1 to 10 explain by means of customary circuit diagrams and give sufficient indication of the apparatus included in a multi-central telephone system constructed in accordance with the principles of the present invention to clearly understand the meaning of the invention. invention.

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   Fig. 11 is a diagram explaining how FIGS. 1 to 8 should be placed end to end (Fig. 8 being substituted for Fig. 3 according to the indications which follow later), to be properly understood in combination with the description which will be given regarding the establishment of certain connections. Fig. 12 is a schematic drawing explaining how to arrange Figs. 2, 8-10 in order to be easy to understand in combination with the description which will be given below of the establishment of certain other connections (fig. 10 being to be substituted for fig. 2 and 7 according to the indications given below. far).



   Considering each figure separately:
Fig 1 shows station A whose line terminates at the central and individual LS line switch, and is accessible to a connector group by means of 101 '-103' conductors The LS line switch has access, together with other switches row, to a group of primary selector translators, one of which is the SR selector translator. The contact panels of the selector translators provide access to the outgoing lines leading to the other central offices in the system, a group of lines leading to each of these offices being accessible on a different floor. A specific floor provides access to a group of call repeater switches, and another floor provides access to a group of local secondary selectors.



  The DT machine for generating current for a call signal, 1T control equipment, including relays 181 and 182, and L-L32 lamps. and the counter

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 subscriber M, are also shown in fig. 1. Subscriber set A is of the usual automatic type.



  The line switch LS is of the known rotary type, having no rest position and walking only in one direction, its advancement being imparted to it by the return stroke of the motor electromagnet acting in combination with it. The selector-translator SR is constructively of the ordinary two-direction vertical and rotary type, but the circuits constitute an essential part of the present invention and will be described in detail in the following paragraphs.



   Fig. 2 shows the local secondary selector S2 and the tertiary selector S3. The selector S2 is part of the group of local secondary selectors which are accessible from a certain stage of the contact panels of the primary selector translators. The contact panels of this group of secondary selectors provide access to the various groups of local tertiary selectors; the selector S2 in particular is part of a determined group. The contacts of the tertiary selector panels giving access to the various groups of connectors. It is further assumed that the plant in question has a sub-plant.

   The lines leading to the sub-central unit are accessible to the contacts of a determined stage of the local secondary selector and leading to the sub-central unit at tertiary arrival selectors, similar to the arrival selector IS, fig. 4, Selectors S2 and S3 are identical with regard to

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 their details from the mechanical point of view and that of their circuits, and are of the well-known vertical and rotary type with two directions. The circuits of these intermediate selectors are modified to meet the needs of the object of the invention and will be described in detail below.



   Figure 3 shows connector C which represents one of the connectors of a certain group of regular connectors accessible to the contact panels of the tertiary selector group of which selector S3 is a part (and also to the panels of the transmitting selector group ringtone which includes the TTS ringtone transmission selector (fig. S),
The panel contacts of connector C have access to a group of lines leading to telephones such as station A ". This line also ends at the individual line switch LS3. Below connector C are shown the equipment. bell, comprising the generator G and the switch I ', the switch I and the dynamo of the not free signal.

   From a mechanical point of view, connector C is of the known two-way vertical and rotary type.



  The connector circuits also form part of the invention and will be described in detail hereinafter. The station An and the line switch LS3 are in all respects identical to the station A and the line switch LS of the station. fig. 1, except that at the line switch LS the fourth conductor for the purposes of the meter has been removed.



   Fig. 4 shows the secondary ar-

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 rive IS to which ends one of the arrival lines leaving from one of the other offices of the network. Lines arriving from other offices * also terminate in secondary arrival selectors. The contact panels of the incoming secondary selectors are directly connected in multiple to the panels of the local concessionary selectors and the incoming secondary secondaries thus have common access to the different groups of local tertiary selectors.



   From a constructive point of view, the arrival selector IS is also of the vertical and two-way rotary type. The circuit arrangement which forms a special part of the present invention will hereinafter be described in detail.



   The right half of fig. 5 shows the arrival transit selector TS which leads to one of the transit lines arriving from the office in which the main ringing table is located.



  There are as many inbound transit lines as are needed to handle the traffic. office in question.



  The contacts of the incoming transit selectors give access to groups of ringing transmission selectors and also to a group of lines leading to the sub-central of the office in question, where these lines also lead to transmitting selectors. similar ringing tones. The transit selector switch is of the known two-way vertical rotary type and is operated according to the known two-wire control system. However, it is fitted with special cam springs for the eleventh pitch, for

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   adapt it to your application in the system described.



   The left half of fig. 5 shows the operator's transit cord 00 at. means of which transit connections are made on lines terminating at the various offices of the system, each line terminating at the transit board at a jack such as the J jack for example. This dordon is of the normal type and does not constitute an essential part of the invention itself. Its circuit will only be described as far as necessary to fully describe other devices controlled by means of cord elements.
Fig. 6 shows the TTS transit transmission selector, which is one of a certain group of transit transmission selectors accessible to the contact panels of the ringing arrival selectors.



   The transit transmission selector contact panels are directly multiple-coupled with the local tertiary selector panels such that the transit transmission selectors and local tertiary selectors have common access to the connectors. From a mechanical point of view, the TTS ringing transmission selector is also of the vertical type and rotary in two directions. The arrangement of the circuits has however been modified for the needs of the object of the invention and will be described later also in detail.



   Fig. 7 shows the FSC frequency selector connector which is, in all reports, identical to connector C (fig. 3) both from the point of view

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 mechanical than that of operation, except that it is provided with an individual frequency selector mechanism FS which is actuated in response to a special digit to choose the frequency of the ringing current to be applied to the called line. .

   The FSC frequency selector connector has access to extension lines and is part of a group of frequency selector connectors accessible from the contact panels of a certain group of local tertiary selectors connected in multiple to the contact panels of a a green group of ringing transmitter selectors, which in the case described will also be assumed to be the group having access to the groups of regular connectors of which connector C.



   In the drawing is shown a line of a station accessible to the FSC connector serving stations A1-A10 and terminating at the exchange at the line switch LS. Set A shown in full, and the other sets of which only the bells are shown, are identical, in all respects, to set A, (fig. 1) except that the call machines are normally connected by a side or the other of the line with the earth, instead of being normally connected across the line conductors. The LS7 line switch is in all respects identical to the LS3 line switch (fig. 3). The operation of the FSC connector will be described as different from that of the C connector.



   Fig, 8 shows the RC rotary connector which is also similar to connector C (fig.3)

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 except that it performs an automatic questing rotary motion after completing its steering rotary motion. Panel donation contacts provide access to groups of lines leading to private sub-offices with the number of their first line as their call number. The RC rotary connector is part of a group of rotary connectors accessible from the contact panels of a group of local tertiary selectors connected in multiple to the contact panels of a determined group of ringing trance selectors which in this case will be assumed to be the group having access to the group of connectors to which connector C. belongs.

   In the drawings are shown the first and last line of a group leading to the private secondary office X accessible at the RC connector. Each line terminates at the main office at an individual line switch such as LS8, and at the secondary office at a jack, for example the J jack. The LS8 line switch is similar in all respects to the LS3 line switch shown in fig. 3. The operation of the RC connector will be described also as it differs from the operation of the C connector (fig. 3).



   Fig. 9 shows the primary selector translator SR 'which closely resembles the primary selector translator SR (fig.1) the difference between the two residing in the way in which the operation of the subscriber's meter is ensured. The primary selector translator SR is arranged so as to ensure the operation of the subscriber's meter on a qua-

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 third conductor, while the primary selector translator SR 'is arranged so as to ensure the operation of the subscriber's meter by the momentary application of the current from a containment battery to the ordinary tripping line on which the the subscriber's counter is connected in this case as soon as a communication is established.

   The particular line serving stations B- - B and terminating at the line switch LS1, and the counter M9 are also shown. My sets B1 -B10 are identical to sets A - 1 A10 The line switch LS9 and the subscriber's M9 counter are similar to the line switch LS and the counter M, except that the Fourth control arm
9 tact has been removed at the LS line switch and meter M9 is plugged into the normal subscriber line 902 'and is set within limits.



   Fig. 10 shows the call repeater switch RV which, together with other similar call repeater switches, is accessible to the contacts of a given stage of the contact panels of the primary selector repeaters. This call repeater switch RV is also of the vertical and two-way rotary type, but its circuits are modified for the purposes of the object of the invention, as will be explained later in detail.

   At the bottom right-hand corner of fig. 10 is shown the special ringing equipment comprising the five ringing generators (which may be the same as those in fig. 7), the switch relay 74 and the switch 1, This switch I comprises two switches provided with conductive segments and insulating segments;

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   -as the drawing indicates, and contact arms for each switch rotatably mounted on the same shaft.



   Figs. 11 and 12 explain how the drawings should be placed in order to follow the descriptions which will be given in the following paragraphs. your devices and the arrangement of the circuits having thus been described in broad outline, a more detailed description of the subject of the invention will now be given and; for this purpose, it will be assumed first of all that the subscriber of station A wishes to talk to the subscriber of station A "± the drawings will be arranged as shown in fig. II).



   To initiate a call, the subscriber of station A first picks up his receiver, thereby bridging the line conductors 101 and 103 and closing a circuit for line relay 106 of the line switch LS. . The line relay 106 is energized on this circuit and performs to the armature 113 the earthing of the normal private conductor 102, thus signaling the line, terminating at the station A "," occupied "at the connectors which have access to it; at the same time it prepares an excitation circuit for the relay switch 105.



  At the armature 114 the relay 106 connects at the same time the test contact arm 118 to the connection of the remais 105 with the motor electromagnet 108. If at this time the line on which the contact arms of the switch are placed is occupied, an excitation circuit is established for the motor magnet 108 from the earth of the test contact on which the arm is engaged

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 EMI13.1
 test contact 118, by the armataié Il rest contact, 1'armature 114, and the work contact, the switch contacts 115 and by the winding of the motor magnet 108 to the battery. The motor electromagnet 108 therefore begins to work in a manner comparable to that of a shaker and moves the contact arms 117-120 forward in search of an available line.

   During this time the switching relay 105 is immobilized due to the earthing of both ends of its winding.



   As soon as a free line has been reached, the magnet motor 108 ceases to operate, and the relay 105, no longer being short-circuited, is energized in series with the motor electromagnet 108. The magnet 108 does not work on this circuit due to the relatively high winding resistance of the relay 105.



  The relay 105 by attracting its armatures prepares the armature 111 a circuit for the meter M of the subscriber and, the armature 110 and its working contact, a locking circuit for itself and cuts, to ammonds 109 and 112 the line conductors with respect to the line relay 106 and the earth, respectively, and prolongs the conversation connection through the intermediary of these reinforcements. and their working contacts, control arms. contact 117 and 120, conductors 121 and 124, normally closed contacts which are controlled by armatures 137 and 141 and contacts normally kept closed by armatures 155 and 156, through the lower winding and the upper winding of the line relay 126 respectively to the battery and to the earth.

   Line relay 126 is switched

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 tee and t'srme, at armature 142 and at work contact, a circuit for trip relay 127.



   Trip relay 127 is energized and makes the following modifications to the circuits: On the armature
144 a ground is placed on the trip conductor 122 thus indicating the line leading to the repeater selector SR as being occupied and on the other hand completing a guard circuit for the line relay 106 of the line switch LS, and this before the line relay 106 which is delayed action, has had. time to abandon its armatures, At armature 147 is prepared a circuit for the lower winding of latch relay 128.

   At armatures 145 and 146 is closed an initial excitation circuit for latch relay 128; this circuit is as follows: from the earth via the armature 150 and the rest contact, the working contact of the armature 145 and this armature, the normally closed springs controlled by the armature 162, the armature 160 and its rest contact; the armature 146 and its working contact, the resistor 136, through the upper bearing of the relay 128, the armature 158 and its rest contact, the rest contact of the armature 141 and this armature, the normally closed springs controlled by armature 164, through the upper winding of series relay 129 and through the winding of vertical magnet 133 to the battery.

   Relay 128 is energized on this circuit and, by actuating armatures 148 and 152, establishes for its own energization a new circuit from earth to the normally closed contacts controlled by the armature. 161, the arma-

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 tare 137 and its rest contact, armature 148 and its work contact, armature 146 and its work contact, resistor 136, through the upper winding of relay 128, the work contact of the arm. mature 152 and this armature, the rest contact of the armature 141 and this armature, the normally closed springs controlled by the armature 164, through the upper winding of the series relay 129, and through the winding of the vertical magnet 133 to the battery.

   At the armature 150 is closed a circuit for the lamp L in series with the relay 181, so that the lamp L lights up and the relay 181 attracts its armatures for a purpose which will be explained more clearly below. . By the attraction of the armature 150, the direct earth of the tripping conductor 122 'is removed, the earthing of this conductor now being ensured by the upper winding of the relay 125.



   The primary selector repeater SR is now in a state to receive the first series of pulses which will be transmitted by the calling subscriber by means of his dial device, all the operations which have been indicated above having taken place in response to the removal of the receiver at the calling station; As soon as the contact arms of the LS line switch have reached in their rotary movement the contact belonged to the line ending at the primary selector repeater SR then free, an acoustic warning signal is transmitted to the calling subscriber by the sending machine of the call signal DT to which the conductor 193 is connected.

   The subscriber who calls, hearing this signal, sat that he can start

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   to telegraph the number of the desired subscriber by means of his dial device.



   In response to the transmission of the first digit of the requested number, the loop straddling the line conductors 101 and 103 is opened a corresponding number of times, thus opening the circuit and pro-
Knocking out a corresponding number of de-energies and re-energizations of line relay 126. Each time relay 126 drops its armature 143, resistor 136 and the top winding of relay 128 are shorted. The resistance of the top winding of relay 128 is relatively large compared to the resistance of the top winding of relay 129 and that of the winding of vertical magnet 133.

   Shorting resistor 136 and the top winding of relay 128 can therefore increase the current flow enough through vertical magnet 133 to produce excitation of the magnet each time the said resistor and said winding are short-circuited, so that the vertical magnet 133 starts to advance the contact arms step by step opposite the contact stage which corresponds to the number transmitted by the dial.



   The trip relay 127 remains energized as long as the pulse emission lasts, because of its usual delayed tripping characteristic. Relay 128 is also kept energized in a continuous fashion although its upper winding is intermittently shorted, its new circuit going from ground through said lower winding.

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 the working contact of the armature 149, this armature itself, the working contact of the armature 147 and this armature, and through the winding of the relay 127 to the battery, and also to the battery on a parallel circuit comprising the armature 142 and its rest contact, as well as the resistor 136 '.



   The series relay 129 is also energized in series with the vertical magnet 133 and is kept energized throughout the duration of the energization of this magnet due to its delayed tripping characteristic. By attracting its armatures, relay 129 closes an initial excitation circuit for the stepper translation relay 131, which goes from earth through the trip conductor 122, the make contact of armature 153 and this armature itself. Likewise, the armature 163 and the break contact, the switch springs 166 which are closed at the first vertical pitch of the switch contact arms and through the winding of the stepping relay 131 to the battery.



   The relay 131 by attracting its armatures closes to the armature 160 the following guard circuit for itself: from the earth through the upper winding of the relay 125, the make contact of the armature 145 and this armature itself, the normally closed springs controlled by the armature 162, the armature 160 and its working contact, the switch springs 165, the working springs 166 and through the winding of the relay 131 to the battery. The circuit for the rotating magnet 134 is also prepared.

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 to reinforcement 159,
At the end of the pulses for the first digit, the I29 relay de-energizes and opens the "primitive excitation circuit from relay 131 to armature 153, at the same time completing the circuit for rotating magnet 134.

   The magnet 134 / attracts its armatures and rotates the contact arms 171-473 so as to engage them on the first group of contacts of the chosen stage of the contact panel, further opening the switch guard circuit with the switching springs. step-by-step trabslation relay 131. This relay 131 then de-energizes and in turn opens the circuit from the magnet to the motor 134 to the armature 159, and, to the armature 160 also its own guard circuit. The magnet 134 is de-energized and closes the switch springs 165.



  If the line leading to this group of panel contacts is at that time occupied the test contact to which the contact arm 172 is engaged will be grounded. A new circuit will be established for the motor relay 131 from the earth on said test contact, the contact arm 172, the armature 162 and its rest contact, the switching springs I65 ,. the working springs 166 and by winding the relay 131 to the battery.

   The relay 131 by attracting its armatures will again close the circuit for the rotating magnet 134, which thereupon attracts its armatures and rotates the contact arms of the switch so as to engage them on the next set of contacts of the panel. , as it has just been described.

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   This step-by-step operation is repeated until a line has been found free, which is indicated by the absence of earth on the test contact assigned to that line.



   It will be assumed that the first line found free at the chosen floor is at that time the line comprising the conductors 174-176. When the contact arms I7I-I72 of the switch are engaged in their rotary movement on the set of contacts 174'- 176 'leading to this line, no circuit is established for the motor relay 131 and the contact arms are not established. therefore stop in this position.

   In addition, since the upper terminal of the switch relay 132 is not in the roasted following circuit is found in a state to cause the energization of the switch relay 132: from earth through the upper winding of the relay 125, the contact of armature 145 and that armature itself, the coil of relay 132, switch contacts 165, working springs 166, and through the coil of relay 131 to the battery.

   The current flowing in this circuit being limited by the relatively high resistance of relay 132, is insufficient to determine the energization of relay 131. Relay 132, on the contrary, attracts its armatures and performs the following circuit changes: A ground potential is established at the trip conductor 175 of the selected line, through the upper winding of the relay 125, the make contact of the armature 145 and this armature itself, the make contact of the armature 162 . Scraper frame itself,

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 the contact arm 172 and the test contact 175 'to which the conductor 175 is connected.

   At the armature 163 is closed a point du'circuit serving to actuate the com comptour M of the subscriber station. With reinforcements 161 and
164 the control circuit is protected by the intermediary of the contact arms 171 and 173, the contacts
174 'and 176' of the contact panels, the conductors
174 and 176 to the local 8% secondary selector switch, while the normal earth and battery connections with the upper and lower conversation conductors are interrupted at the springs actuated by armatures 161 and 164.

   The control circuit now extends from earth to the normally closed springs controlled by the armature 208 of the secondary selector S2, the conductor 174, the contact 174 'of the panel, the contact arm 171, the armature 161 and the working contact, the armature 137 and the rest contact, the armature 148 and its working contact, the armature 146 and the working contact, the resistor 136 the upper winding of the relay 128, the working contact of the armature 152 and this armature, the rest contact of the armature 141 and this armature, the working contact of the armature 164 and this armature, the contact arm 173, panel contact 176 ', conductor 176, normally closed springs controlled by armature 211', winding of relay 202, and by winding vertical magnet 204 to the battery.

   Grounding the shunt conductor 175 closes a circuit through the normally closed contacts controlled by armature 209, through the upper winding of the two-way relay.

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 stages 201 to the battery. The energization of the upper winding of the relay 20i only causes the attraction of the armature 210 which then opens a point in the circuit of the tripping electromagnet 206 and prepares other circuits which will be described. further.



   In response to the next digit transmitted by means of socadran by the subscriber of. station A, resistor 136 and the upper winding of relay 128 are again shorted a corresponding number of times, so that the vertical magnet 204 is energized in the same way in which The vertical magnet 133 of the primary selector repeater SE has been excited. By attracting its armature, the magnet 204 brings the contact arms 221-223 to the level of the contact stage of the panel which corresponds to the number transmitted by the dial.

   The relay 202 which works in series with the vertical magnet 204 and which being delayed tripping remains energized during the transmission of this series of pulses, closes the following circuit: from the earth through the armature 210 and its working contact , the working contact of the armature 212, the working springs 218 which are (closed at the first vertical pitch of the switch contact arms, through the winding of the relay 203 to the battery.



  The relay 203 being energized closed at the armature 213 a guard circuit for itself and prepares, at the armature 214 a circuit for the rotating magnet 205. At the end of this series of pulses, the series relay 202 de-energizes and leaving the springs controlled by frame 212 to close, woman a circuit for the magnet

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 rotary 285. The magnet.: - 205 is de-energized and imparts to the contact arms 221-223 in a rotary movement which engages them on the first contact jea on the chosen stage of the contact panel and at the same time opens to the switching springs 215, the relay guard circuit 203.

   The relay 203 is de-energized and opens the circuit of the rotating magnet 205 which, releasing its armature, again closes the interrupted contacts 215. If the line leading to this contact set is occupied the test contact on which is engaged the test contact arm 222 will be found to be earthed and a circuit for the relay 203 will be closed again but the earth through the said test contact the contact arm 222, the armature 209 and its contact rest, the switch contacts 216 and 215, the working springs 218 and by the winding of the relay 203 to the battery.

   The alternating excitation of the motor relay 203 and of the magnet 205 then takes place in a manner identical to that in which the stepping translation relay 131 and the rotary magnet 136 of the primary selector repeater SR operated, thus forcing the selector S2 has contact arms on the first set of contacts of the contact panel which leads to an unoccupied line, / which is indicated by the absence of earth at the test contact. The relay 201 is meanwhile prevented from executing its second phase because the two terminals of its lower winding are earthed.



   The line chosen will be the one that includes conductors 22-226. Since the arm

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 contact 22 does not encounter any earth potential this time) the next circuit which goes from earth through the trip conductor 175, through the lower winding of the relay 201,, the switch contacts 215, the working springs 218 and winding the relay 203 to the battery can energize the relay 201 in plain mode. Bar due to the strong resistance of the lower winding of relay 201, the current flowing through the circuit is not enough to reassure the excitation of relay 203.

   The relay 201 being energized; by its second winding, attracts all of its armatures which results in the following: At armature 209, the tripping conductor 225 of the local tertiary selector S3 is earthed by the conductor trigger 175, which is ground, the working contact of the armature 209 and this armature itself, the contact arm 222 and the test contact 225 'to which the conductor 223 is. connected. The circuit for the upper winding of the relay 201 is at the same time opened by the separation of contacts controlled by the armature 209.



  At armatures 208 and 211 the control circuit is extended to the selector S3 the upper conversational conductor is earthed by springs influenced by the armature 208 'while the lower conversation conductor is connected. to the battery to the springs influenced by the armature 211 ', via the vertical magnet 204;' in series with relay 202 '.



   Selector S3 is in all its details identical to selector S2 and acts obeying the series

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 following pulses which is transmitted by the subscriber who calls by means of his dial device, in a manner identical to that in which the selector S2 acts, by placing his contact arms opposite the contact stage of the panel that corresponds to the transmitted number, and then choosing an unoccupied line of this stage.



   It will be assumed that the line chosen is the one which includes conductors 234 - 236 terminating at connector C. Taking possession of this line therefore results in the closing of a circuit for the upper winding of the two-stage relay.
301. This circuit is as follows: from ground through trip conductor 235, the rest contact of armature 313, and the top coil of relay 301 to the battery. Relay 301 acts by its first degree and attracts only its armature 312, thus opening a point of the circuit of the trip magnet 308. On the other hand a circuit is closed for the switching relay 305 from the earth through the conductor. tor 235 by the normally closed vertical working springs 333 and the lower winding of the relay 305 at the battery.

   The relay 305 reacts and prepares the armature 328 for a guard circuit for itself, coupling to the armature 326 the vertical magnet 306 in series with the series relay 302 and at the same time raising the magnet. rotary 307 switched off. The relay 305 operates this time as a switching relay as will be explained later. By this close possession of the line the control circuit is at the same time extended

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 up to connector C, the upper conversation conductor now being grounded to the springs influenced by armature 311 and the lower conversation conductor connected to the battery via the vertical magnet 306 in series with the relay 302 to the springs influenced by the armature 315.



   In response to the transmission of the next digit by the calling party, resistor 136 and the top winding of relay 128 are again shorted a corresponding number of times and operate vertical magnet 306 of the relay. so as to cause it to bring the 341343 contact arms opposite the corresponding contact stage of the panel. The series relay 302 acts in series with the vertical magnet 306 and, thanks to its delayed tripping, remains energized as long as the transmission of the series of pulses lasts.

   The guard circuit of relay 305 is closed at armature 317 and its working contact so as to keep this relay energized for the duration of the vertical movement of the contact arms, the initial energizing circuit for the contact arm. lower winding of relay 305 being interrupted or at the first vertical pitch of the contact arms, to the vertical working spring 333.



  The attraction of the reinforcement 316 remains this time ineffective. At the end of this series of pulses, relay 302 is de-energized and opens the guard circuit of the lower coil of relay 305 to armature 317. Relay 305 is de-energized and couples the rotary magnet. 307 again in series with relay 302 to armature 326 simultaneously carrying out the

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 vertical magnet 306 switched off.



   In response to the next series of pulses transmitted by the calling subscriber, the rotating magnet
307 is energized so as to engage the contact arms on the set of panel contacts corresponding to the number transmitted, this set of contacts being the one to which the line of the called station, A ", namely the contacts 344 # 346 of the panel, ends. Relay 302 again draws its armatures during the transmission of this series of pulses, but this time wired in series with rotating magnet 307, and prepares the straightened circuit for test relay 304 to armature 316 and its working contact For the subsequent operations of connector C, everything now depends on whether the called line is currently busy or free.



   If the line terminating at station A "is busy at this time, panel contact 345 will be found to ground and contact arm 342 when engaging contact 345 closes a circuit for test relay 304. from earth on contact 345 through contact arm 342, armature 316 and its make contact, rest contact of armature 327 and this armature, and through the winding of test relay 304 to the drums.

   Relay 304 attracts its armaturess and opens at armature 323 a point of the repeater signal circuit, closes at armature 322 a point of the circuit for the "not free" signal and prepares for itself a guard circuit to armature 321. Shortly after the end of this series of pulses, the step 302 is

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 de-energizes by closing this time a guard circuit for the test relay 304, allowing the springs influenced by its armature 316 to close.

   The armature 317 on falling at the same time closes the following circuit for the lower winding of the two-degree relay 301: from earth through the tripping conductor 235, the rotating working springs 331 which closed at the first rotary step of the contact arm, armature 317 and its rest contact, vertical work springs 332 which happened to be closed first step vertically into contact arm and through the lower winding of relay 301 to the battery.



  Exciting its lower coil magnet this relay to its second degree such that it attracts all of its armatures, with the following results A. 1 armature 313 the circuit for its upper coil is interrupted and at armatures 311 and 315 the earth and the battery are cut off respectively from the conductors 234 and 236, which causes the cut-out of the guard relay 128 of the primary repeater selector SR. Relay 128 by de-energizing opens the circuit from control relay 181 to armature 150 and at the same time puts the trip line directly to earth, Trip of armature 151 connects the lower winding of the bat relay laughs 130 to the lower conversation conductor.

   The triggering of the reinforcements 148 and 152 establishes a reversing circuit from station A to connector C, so that the calling subscriber can hear the "not free" signal emitted by the machine BM for the "not free" signal, the potential of this throwing signal transmitted to the con-

  <Desc / Clms Page number 28>

   dactear of lower conversation from the common conductor 391 of this not free signal, by the rest contact of the armature 319 and this armature itself, the armature 322 and its work contact, and the conductor 236 hence it is transmitted to the station of the subscriber who called.

   Receipt of this signal alerts the calling subscriber that the desired line of this signal alerts the calling subscriber that the desired line is currently busy, so that he will hang up his receiver with the intention of calling back a little later. .



   The re-hooking of the receiver determines the triggering of all the switches which had been operated in a manner which will be described in detail below.



   Coming back to the point where other connector operations were dependent on the calling line's "not free" or "free" state, it will now be assumed that the line terminating at station A "is free at the calling line. time of attempting to connect to this line.



   In this case the test relay 304 is not energized since the contact 345 of the panel is not earthed. Under these conditions, the relay 302 when it trips at the end of the last series of pulses, closes the following circuit: from the conductor 235 earthed, by the 'rmature321 and its rest contact, by the upper winding of the relay 305, the rest contact of the armature 316 and this armature the contact arm 342, the contact 345, the winding or switching relay 361 of the line switch LS, the switch contacts 369 and 'winding of

  <Desc / Clms Page number 29>

 magnet 363 to the battery.

   The relays 305 and 361 are energized on this circuit, but following the large resistance of the switching relay 361 the current flow is insufficient to determine the excitation of the magnet 363. By attracting its armatures the relay 305 closes to the armature 328 a guard circuit for itself, grounds panel contact 345 to armature 325 through contact arm 342, thus indicating station line A "as" not free ", and closes the ringing circuit to the frames 324 and 329 for ringing the subscriber of station A ".



   The ringing circuit is as follows: from the earth via the rest contact of the armature 318 and this armature, the armature 324, and its work contact, the contact arm 341, the contact 344 of the contact panel, the line conductor 371, through the bell of station A ", the line conductor 372, the contact 346 of the contact panel, the contact arm 343, the working contact of the armature 329 and this armature, the armature 320 and its normally closed contact, the lower winding of the bell cut-off relay 303,

   the common ringing conductor 390 to which are connected alternately the current of the battery superimposed on the ringing current of the generator G and the direct current of the battery. When energized, relay 361 disconnects the respective normal connections of the line conductors with the earth and the battery without connecting the contact arms 380-382 thanks to the usual mechanical locking mechanism between the relays 361 and 362.

   Relay 301 is obviously also actuated in this

  <Desc / Clms Page number 30>

 case on its second winding at the end of the last series of pulses, the circuit of its lower winding having been closed by the tripping of the armature 317, the relay 128 of the selector-repeater
SR is then de-energized and prepares the conversation circuit by releasing its plates 148 and 152 in the manner described above. The ringing of station A "will now operate under the influence of the ringing current until the subscriber of station A" answers.



   By picking up his receiver to answer the call, the subscriber of station A "establishes a direct bridge over line conductors 371 and 372 and thereby closes a direct current circuit for the ringer cut-off relay 303. This relay 303 attracts its armatures and closes to the armature 319 "the following locking circuit for its upper winding: of the earth of the tripping conductor 235 by the armature 319 'and its working contact, the upper winding of the relay 303 and by resistor 309 to the battery. The ringing circuit is disconnected from the 318 and 320 armatures and from the conversation circuit finally completed between the subscribers of station A and station A "Triggering of armatures 148 and 152 connects the relay for supplying battery current 130 directly across the called line.

   The relay 130 by attracting its armatures disconnects at the armature 158 one of the terminals of the relay 128 from the lower conversation conductor, inverts to the armatures 155 and 156 the connections of the earth and of the battery with the calling line. , and closes with the frame 157 a

  <Desc / Clms Page number 31>

 circuit for the magnet 116 of the subscriber's meter M, in parallel with the lower winding of the relay 129.



  The M counter records the call. The relay 129 is energized and locks the trip line to the armature 153 keeping the magnet circuit 116 closed until the moment when the communication is interrupted. In this way the counter M is prevented from being distorted by the swinging of the switch hook from the receiver to the called station. Reversing the battery and earth connections with the calling line does not play a role in establishing the described call but can be used to secure the collection of a coin when a call is made from a caller. prepaid station and is therefore shown here by way of example.

   The calling subscriber and the called subscriber can now chat together, relays 125 and 130 being the only bridges on the line, the conversation current being supplied to the calling subscriber through the turns of the relay coil. 125 and, for the called subscriber, by the windings of the relay 130.



   At the end of the conversation, the two subscribers will hang up their receivers. By hanging up their receiver, the called subscriber opens the direct current bridge on the line conductors and thus de-energizes the battery current supply relay. 130. This relay 130 is de-energized, leaving its reinforcements dark to their rest position. The direction of current flow at the calling station is restored to its normal direction by triggering armatures 155 and 156 and a circuit for the control lamp

  <Desc / Clms Page number 32>

 
 EMI32.1
 The and relay 182 is closed when reset tare 157. By hanging up his receiver the calling subscriber interrupts the direct current bridge on the line conductors 101 and 103 and thus opens the circuit for the line relay 126.

   This relay 126 is de-energized and opens at armature 142 the trip relay circuit 127. Relay 127 de-energizes and abandons its armatures, with the following result. At the frame
144 ground is removed at the trip lead 122 and a circuit; comprising the working springs 168, which were found closed at the first vertical pitch of the contact arms, and the armature 318, is closed for the trip magnet 135. By its operation the magnet 135 returns the contact arms 171 -173 to their normal position. Removing the ground of the trigger conductor 122 simultaneously opens the guard circuit for the lower winding of the relay 129 and removes the ground of the conductor 123 of the meter.

   The relays i29 and 105 then trip and let their armatures return to their normal position, and the magnet 116 of the subscriber's meter M returns to its normal position.



   By releasing the armature 145 the earth potential is removed from the trip conductors U22 ', 175'. 225 and 235 which are connected in series and passing through the primary selector-repeater SR, the secondary selector S2. the tertiary selector S3 and the connector C. Removing the earthing of these conductors causes the switching relay 132 of the selector-repeater SE ?, of the switching relay 201 of the selector to be de-energized.

  <Desc / Clms Page number 33>

 secondary S2, from the switching relay 201 'to the tertiary selector S3 and from the switching relay 301 of connector C.

   The de-energization of the relay 201 determines the closing of a circuit for the trip magnet 206 from the earth by the armature 210 and its rest contact, the vertical working springs 217 which closed at the first vertical step of the arms of the contact 22.1-223 of the sa selector, and the winding of the triggering magnet 206 to the battery.

   The tripping magnet 206 acts and causes the contact arms 221-223 of the selector 8 2 to be stored in their normal position. A circuit is also closed for the tripping magnet 206 'of the tertiary selector S3 so that this magnet being energized, trips contact arms 231-253 of selector S3 to let them return to their normal position A circuit is also closed for trip magnet 308 of connector C from earth through the rest contact of armature 312 and this frame, the vertical working springs 330 which had closed at the first vertical step of the connector C and the winding of the triggering magnet 308 to the battery. Magnet 308 is energized and causes contact arms 341-343 of connector C. to be returned to their normal position.

   Removing the earth potential at the tripping conductor 235 also opens the guard circuits of a bell disconnection relay, 303 and of the switching relay 305 so that these relays de-energize and allow their armatures to resume their position. All the devices used to establish the communication described above are then returned to their position.

  <Desc / Clms Page number 34>

 normal and the assembly is ready to be used again. to establish new communications.



   On any network with multiple central units, provision must be made for the means to pass calls from one subscriber from one central to another subscriber from another central. In telephone systems as they are generally arranged heretofore, an outgoing repeater is provided each time for each line leaving to another central, in order to repeat the pulses to this other central.

   On the contrary, the system which forms the subject of the invention completely avoids the use of outgoing repeaters, the lines connecting one control unit to the other being accessible directly to the contact panels of the primary repeater selectors of the unit. type shown in, FIG. 1 (or in fig. 9 which will be described later) and leading directly to arrival repeater selectors of the type shown in fig 4. To describe the operations to be carried out to establish a call from a subscriber of an office with a subscriber of another office, it will be assumed that a specific subscriber of any remote office desires communication with the subscriber of the set Au (the drawings to be placed retort indicates this in fig. 11). .



   To establish this communication the subscriber of the remote office picks up his receiver and telegraphs the number of station A "in the directory. In response to the removal of the receiver at the calling station, the individual line switch of said station goes to the search for a line leading to a free primary repeater selector, which may be identical to the selector

  <Desc / Clms Page number 35>

 
 EMI35.1
 primary repeater tor shown in fig, l.

   In response to the transmission of the first digit of the number called the primary repeater selector qfathers as explained above and places its contact arms in front of the contact stage of the contact panel to which lines are accessible. leading to the office which serves the subscriber at station A ", to then automatically choose from among these lines one which is free.

   It will be assumed that the line chosen is that comprising the conductors 401 and 402 terminating at the secondary arrival selector IS, fig. 4, Taking possession of this line closes a circuit going from the earth via the rest contact of the armature 419 of the arrival selector IS and this armature itself, by the winding of the lugne relay 403, the line conductor 401, through a loop comprising a resistor and the guard relay of the selected primary repeater selector similar to resistor 136 and relay 128 of the SR repeater selector, through the line conductor
402, armature 420 and its normally closed contact, through the upper winding of the limited impulse relay
405 of the selector arriving IS at the battery. The resistance of the circuit traced above is large enough to prevent relay 405 from operating this time.



   Relay 403 is basically shunted by the earth link via the rest contact of armature 418, this armature itself, and resistor 440, but is still actuated on the circuit which has just been traced. , and closes to the frame
415 a circuit for the release relay 40 which, by controlling, opens to the armature 428 a point of the circuit

  <Desc / Clms Page number 36>

 of the trip magnet 413 and connects the earth potential to the trip conductor
450.

   By attracting its armature, relay 403 on the other hand closes a circuit going from the earth via the normally closed springs controlled by armature 431, armature 416 and its working contact, armature 417 and its contact of rest, the resistor 441, the winding of the guard relay 406, the normally closed vertical working springs 436, the normally closed springs which the armature 435 controls, the rest contact of the armature 449 and this armature it - even, the winding of the 409 series relay and the winding of the vertical magnet 412 to the battery.

   The current circulating in this circuit is not enough to actuate this time the magnet 412 and the series relay 409, but the guard relay 406 is energized and puts in bypass, at the armature 424, the working springs. vail 436 which open at the first vertical step of the contact arm, the relay 406 prepares at the same time for the armature 433 the guard circuit dh step-by-step advance relay 407 and for the armature 425 a circuit de-energization for the pulse relay 405.



   In response to the following series of pulses telegraphed by the calling subscriber, the resistance and the relay of the repeater selector chosen at this office, and which are respectively similar to the resistor 136 and the relay 128 of the selector SR, fig. 1, are short-circuited by the contacts of the line relay a number of times corresponding to the number telegraphed by means of the dial, as described above.

  <Desc / Clms Page number 37>

 



  Each time this resistor and relay are shorted, the current flow through the circuit traced above and including the two line conductors in series, is increased enough to cause the limit relay 405 to close. By attracting its armature this relay 405 closes to armature 42 'a circuit for its lower winding, went from the earth through armature 422 and its work contact, armature 425 and its work contact, resistor 442, the normally closed springs controlled by armature 419, and the lower winding of relay 405 at the battery.

   Relay 405 is differential winding and its windings are proportioned such that the magneto-motive force generated by the current in the upper winding when the resistance and the impulse relay winding of the primary repeater selector are started. -circuit, is greater than that produced by the lower winding, For this reason the relay 405 remains energized during the time that the resistance and the impulse relay of the repeater primary selector are short-circuited, but as soon as the short-circuit is removed at said relay and in said resistor, the flow of current from the upper winding of relay 405 is magneto-reduced,

   so that the force / matrix produced by the current of the lower winding is greater than that produced by the current of the upper winding. Relay 405 therefore de-energizes immediately and, in doing so, opens the circuit of its own lower winding to armature 422. In this way, pulse relay 405 operates perfectly.

  <Desc / Clms Page number 38>

 synchronism with the line relay of the primary repeater selector. Each time relay 405 attracts its armature, resistor 441 and relay 406 are shorted. This results in increased current pulses to the circuit of magnet 412 and series relay 409.

   The magnet 412 is therefore actuated to lift the contact arms 451-453 of the arrival selector IS au. contact level of. sign. contacts that correspond to the number transmitted by the subscriber's dial.



   The serial relay 409 acts in series with the magnet 412 and remains energized in interrupt for the duration of the transmission of the series of pulses, due to its characteristic of delayed tripping relay, and closes a circuit for the relay. step by step translation 407 ,. This circuit is as you know: from the earth through the armature 428 ,. and its working contact of the armature 429 and this armature, the armature 434 and its rest contact, the working springs 437 which feels closed at the first vertical step of the contact arms of the switch, and through the winding of the step-by-step relay 407 to the battery.

   The relay 407 attracts its armature and woman to the armature 426 a circuit going from the earth through the armature 423 and its work contact, the armature 426 and its work contact, the switching springs 439, the springs of work 437, and by winding the relay 407 to the battery. At the armature 427 is prepared a circuit for the rotating magnet 414.



   At the end of this series of pulses, the series 409 relay trips and closes the next circuit.

  <Desc / Clms Page number 39>

 for magnet 414: from the earth through armature 428 and its working contact, the normally closed springs controlled by armature 429, the working contact of armature 427 and this armature, and through the winding of the rotating magnet 414 to the battery. Triggering armature 429 also opens the initial drive circuit of step relay 407. Magnet 414 being energized rotates contact arms 451-453 to engage them on the first. pair of contacts of the stage chosen and at the same time opens the guard circuit of relay 407 to the switching springs 439.

   The stepping relay 407 trips and opens the circuit from the rotating magnet 414 to the armature 427, so that the magnet 414 returns to its original position and closes the switching springs 439 again.



  If the line accessible on this set of contacts is occupied, earth potential will be encountered at the test contact on which the contact arm 452 is engaged and the relay 407 will again be de-energized.



  The stepping relay 407 and the magnet 414 thus working alternately and move the contact arms so as to engage them in the known manner on a set of contacts of the panel to which an occupied line ends. When the contacts to which the unoccupied line terminates are reached - these contacts will be assumed to be the contacts 454 '- 456' belonging to the line comprising the conductors 454-456 - the contact arms 452 do not

  <Desc / Clms Page number 40>

 will encounter no earth potential and the next circuit which goes from earth through armature 428 and its working contact, winding of relay 411, switch contacts 439, working springs
437, and the winding of the relay 407 to the battery, becomes capable of energizing the switching relay 411.



  Because of the resistance of the switch relay 411, the current flow in this circuit is insufficient to ensure the operation of the step by step advancement relay 407. The switch relay 411 on the contrary attracts its armatures and makes the following changes of the circuits: A armature 433 tripping conductor 455 is earthed through armature 428 and its make contact; the armature 432 is prepared a circuit for the switch relay 404, the initial excitation circuit of the relay 407 is interrupted at the armature 434;

   and at the armatures 431 and 435 the earth and the battery connected via the magnet 4I2 are cut off from the large conversation conductors by the separation of the normally closed springs which control these armatures, and the circuit of control is extended, via the contact arms 451 and 453, the contacts 454 'and 456' of the contact panel, and the conductors 454 and 456 to the tertiary selector S3 where the earth and the battery are normally connected to conductors 454 and 456 respectively via magnet 204, so as to keep the circuit for guard relay 406 intact.

  <Desc / Clms Page number 41>

 of the IS arrival selector.

   Extending earth over trip conductor 455 indicated that selector S3 is not available AND causes the two-degree relay 201 'to be energized by winding its first degree, thus preparing the selector for its operation.



   In response to the next series of pulses transmitted by the calling subscriber by means of its dial, the relay 405 is again actuated a corresponding number of times and causes the relay 406 and the resistor 441 to short-circuit a number. of times equal. The vertical magnet 204 of the tertiary selector S3 is therefore actuated and brings the contact arms step by step in front of the contact stage of the contact panel which corresponds to the transmitted digit. At the end of this operation the selector S3 performs the automatic rotary operation and chooses in the manner already described above a line ending in an unoccupied connector, which will be assumed to be the line ending in connector C.



   In response to the next two digits transmitted by the subscriber calling for help from his dial device, connector C is caused to engage its contact arms on the contacts to which the line of the requested subscriber station ends. After the rotational operation of connector C, the switching relay 301 draws its armatures in the manner previously described and interrupts the normal connections of the line conductors 234 and 236.

   This interruption causes de-energization of guard relays 406 of the arrival selector IS.

  <Desc / Clms Page number 42>

   He. The result is the closing of a circuit for the switching relay 404 to the armature 423 and, at the armature 424 the reestablishment of the connection of the upper coil of the relay 410 which supplies the battery current. , with the lower conversation conductor.

   Relay 404 attracting its reinforcements removes, at reinforcement 418 the partial shunt of relay 403, disconnects at reinforcements 419 and 420 the earth and the battery from the incoming line conductors and replaces a bridge. high resistance comprising the relay 403, the resistor 442 and the resistor 443, and connects, to the armature 417, the upper winding of the relay 410 for supplying the battery current with the upper conversation conductor via armature 416. The disconnection of the earth and the battery from the incoming line conductors determines the de-energization of the guard relay of the primary repeater selector at the remote office which is similar to relay 128 of the repeater selector S R .



  The despitation of this guard relay connects the battery current distribution relay similar to relay 130 of the horse-drawn primary repeater selector S R on the line conductors leaving the office. IS arrival selector relay 403 is now energized by battery current which is supplied to the line conductor by said battery current distributor relay. The ralis 403 will be momentarily de-energized while the SR selector-like 128-like guard relay de-energizes and connects the battery current distributor relay across the

  <Desc / Clms Page number 43>

   line conductors; this will have no detrimental effect since the relay 408 has a different trigger and will not be de-energized although its circuit is momentarily interrupted.

   The remote desktop primary selector switch battery current distributor relay does not act in series with relay 403 and resistors 442 and 443 due to insufficient current flow.



   Once the contact arms of the connector brought by their rotary movement on the contacts of the panel to which the line leading to the desired station ends, the line of this station is probed in the manner described above to know if it is occupied or free. If the line is busy at this moment a "not free" signal will be transmitted again to the station which calls and in response to this signal the subscriber who is called must hang up his receiver and thus determine the initiation of the communication of the telephone. way which will be described later.

   If the requested line is free, a current for a warning signal will be transmitted to the conductors of the line to warn the subscriber of the called station A ",
Assuming that the line of set A "is free when the called subscriber picks up his receiver to answer the call, the ringer disabling relay acts and the direct current bridge is then established on the line conductors. 234 and 236 activates the battery current distributor relay 410 of the arrival selector IS.

   As soon as the relay 410 is activated, the resistors 442 and 443 are switched on.

  <Desc / Clms Page number 44>

 short circuit to the armature 430 and thus increase the current flow to the circuit are part of the battery current distributor relay of the primary repeater selector of the remote office and the line conductors connected in series so that the current happens to be sufficient to operate said battery current distributor relay.

   The effects produced by the operation of the battery current distributor relay of the primary selector repeater of the remote office are the same as those produced by the relay 130 of the selector repeater SR explained on the occasion of the setting. previously written about the communication between the subscriber of set A and that of set A ". Conversation communication is thus established and the two subscribers can chat together.



   At the end of the conversation the daux subscribers hang up their receiver. Hanging up the receiver at the called station interrupts the direct current bridge on the line conductors and thus opens the circuit of the battery current distributor relay 410 to the arrival selector I S. Tripping of relay 410 cancels the short-circuiting of resistors 442 and 443. The reintroduction of resistors 442 and 443 in the circuit comprising the battery current distributor relay of the primary repeater selector at the remote office determines the deactivation of this relay which then abandon its frames.

   Hanging up the receiver at the calling set opens the selector line relay circuit.

  <Desc / Clms Page number 45>

 primary repeater of the remote office so that this relay is switched off and interrupts the circuit of which the battery current distributor relay identical to relay 130, the two line conductors 411 and 402 and the relay in series are part, and determines also, in the manner described above, the triggering of the primary repeater selector. Relay 403 trips and opens at armature 415 the trip relay circuit 408.

   Relay 408 trips and, by releasing its armature 428, removes the earth of the trip conductors 450, 455 and 235 connected in series and extending through the arrival selector IS, the tertiary selector S3 and connector C. At the same time is closed a circuit for the tripping magnet 413 which goes from the earth through the armature 428 and its rest contact, the working springs 438 which close at the first vertical step of the contact arm, and through the winding of the trigger magnet 413 to the battery.



  Magnet 413 begins to operate and returns the contact arms to their rest position. Removing the earthing of the tripping conductor 450 interrupts the circuit of the switch relay 411 which, by letting its armatures fall to their rest position, opens the circuit of the switch relay 404 to the armature 432. The relay 432 is thus located. de-energized and let the frames fall back to the rest position. Removing the grounding of the 455 and 235 trip conductors brings the se

  <Desc / Clms Page number 46>

 tertiary reader S3 and connector C in their rest position, as described above.



   In order to facilitate the establishment of a transit or transfer connection from the main transfer board to subscribers in the locality, a new type of transit transmitter selector has been created, specially arranged to meet the needs of the present. invention. To describe the operation of this transmission selector and of the new connector which is applied to it when it is used in a communication in transit, it will now be assumed that a communication in transit is requested with the subscriber of the set. A ". (The drawings must be arranged as shown in fig. II). In the system considered it is assumed that the main transit switchboard is located in a central office from which transit lines leave to the other offices of the network .

   It will also be assumed that the transit operator at the main transit panel set answers the transit call received through the CC cord circuit, fig. 5, and that having learned the subscriber's number requested, it inserts the call plug P 'of the CC cord into the jack of an unoccupied transit line terminating at the office which serves the called subscriber. This line will be assumed to be the one comprising the SOI and 502 conductors leading to the office in question at the T S selector.



   Having inserted the P1 plug into the J jack, the transit operator telegraphs the call number of the requested subscriber using her rotary device. In response to the transmission of the first digit

  <Desc / Clms Page number 47>

 of the number requested, the selector TS places its contact arms in front of the level of contacts corresponding to the number transmitted by the dial and then automatically starts to turn to place its contact arms 551- 553 on a set of contacts of the panel to which a free line ends. The free line chosen is, it will be assumed, the one comprising the conductors 554-556, accessible to the contacts 554 'and 556' of the panel.

   It should be noted that the first digit of the number requested for the transit telephone operator is the second digit of the call number of the desired extension since, by completing her call manually, she chose the office to which the call must be forwarded. As soon as it is taken possession of the line comprising the conductors 554- 556 terminating at the transmitter selector in transit TTS the control contact 555- is earthed to indicate that the line is occupied and a circuit is closed for the;

  line relay 605 of the transmitter selector in transit TTS, circuit which goes from the earth through the armature 622 and its rest contact, the conductor 556, the contact 556 'of the panel, the contact arm 553, the contact of armature 522, and this armature itself the line conductor 502, the ring of the jack J, the ferrule of the plug P ', the contacts 503;

   the lower winding of the winding to the right of the repeater coil R5, the winding of the polarized relays 502, the upper winding to the right of the repeater coil R5, the contacts 506 and 504, the tip of the plug P '. the tip of the jack J, the driver

  <Desc / Clms Page number 48>

 tor 501, armature 521 and its working contact, contact arm 551, panel contact 554, conductor 554, normally closed springs controlled by armature 623, normally closed springs controlled by armature 628, and by; the top winding of the 605 line relay to the battery.

   Line relay 605 by attracting its armatures opens to armature f532 the short circuit of resistor 619 and the upper winding of guard relay 608, and closes a circuit to armature 631 for trip relay 606. Relay 606 attracts its armatures and makes the following circuit changes: at armature 633 conductor 655 is grounded to indicate that the line is busy and to establish a guard circuit for the TS selector, all this before the trip relay; of the selector T S has had time to release it. One point of the trigger magnet circuit 613 is open at armature 634.

   The circuit of the series 609 relay is prepared at the armature 635, the relay 609 being kept de-energized this time due to the earthing of its upper terminal through the make contact of the armature 631 and of this armature. herself. To the armature 636 is closed a circuit going from the earth established on the tripping conductor 555 through the armature 633 and its working contact, the normally closed springs that the armature 648 controls, the armature 646 and its rest contact, the armature 636 and its work contact, the resistant 619, by the upper winding

  <Desc / Clms Page number 49>

 of the relay 608, the armature 624 and its rest contact the springs influenced by the armature 652 and by the winding of the vertical magnet 612 to the battery.



  Due to the resistance of the top winding of relay 608 and resistor 619, the current flowing in this circuit is not strong enough to operate magnet 612. Relay 608 is energized on the contrary and on. attracting its armatures operates the following changes of circuits: At armature 641 and its working contact is closed a circuit for the control relay 690 and the lamp L6 in series, while at the same time a circuit is prepared for the lower winding of relay 608.

   At armatures 642 and V650 a new circuit is closed for the upper winding of relay 608 going from earth through the springs. normally closed controlled by armature 647, armature 640 and its make contact, armature 636 and make contact, resistor 619, the upper winding of relay 608, the work contact of the ar - mature 642 and this frame itself, the normally closed springs controlled by the frame 652 and by the winding of the vertical magnet 612 to the battery.



     In responds to the next digit transmitted by the line relay transit operator 605 is de-energized and re-energized a corresponding number of times.



  As a result, resistor 619 and the top winding of relay 608 are shorted an equal number of times to armature 632 and its normally closed contact, causing corresponding pulses of greater current. circuit current

  <Desc / Clms Page number 50>

 vertical magnet 612. Obeying these impulses 1 (vertical magnet 612 starts to operate and places contact arms 661-664 opposite the contact stage of the panel corresponding to the transmitted number.



   Each time relay 605 is de-energized the earth potential is further cut off at the upper terminal of the series 609 relay and it is replaced by battery current via resistor 615. by means of the armature 631 and its rest contact. Relay 609 is therefore energized on the circuit going from earth through its own winding, the opening contact of the armature 635 and this armature to the battery, by the armature 631 and its closed contact and the resistance 615 and to the battery also by the winding of relay 606.



  Each time the relay 605 is energized again during the pulses, the relay 609 is short-circuited and, by virtue of its short-circuiting, acquires the character of a delayed tripping relay. so that it does not de-energize during the transmission of a series of pulses. Attracting its armor, relay 609 closes to armature 644 an initial energizing circuit for the stepping advance relay, running from the ground of the trigger lead 555 through the make contact of the switch. armature 644 of the armature itself, the rest contact: of the armature 650 and this armature. the working springs 654 which closed at the first vertical step of the contact arms and by the motor relay winding 610 to the battery.

   The 610 relay attracts its reinforcements

  <Desc / Clms Page number 51>

 and prepares, at the armature 645 a circuit for the rotating magnet 613 The relay 609 for its part closes to the armature 643 a circuit for the lower winding of the relay 608, so as to ensure the continuous operation of the relay. 608 during the transmission of the pulses, that is, during the time that its upper winding is short-circuited. Relay 610 closes at armature 646 a self-protective circuit which runs from the ground of trip conductor 555 through the normally closed springs controlled by armature 648, armature 646 and its contact contact. work, the switch springs 653, the work springs 654 and by winding the relay 610 to the battery.



   At the end of this series of pulses, line relay 605 is energized again and remains energized continuously since relay 609 is again permanently shorted to armature 631 and its contact of work, so that he becomes deexcited. Armature 644 on tripping closes a circuit for rotating magnet 613. The circuit runs from ground to trip conductor 555 through the springs driven armature 644, the NO contact on armature 645 and this armature itself and by winding the rotating magnet 613 to the battery? When triggering, armature 643 closes the circuit for control relay 690 again.

   The rotating magnet 613 is energized on the circuit traced above and rotates the contact arms 661-664 to engage them on the first set of contacts on the control panel.

  <Desc / Clms Page number 52>

 the selected stage and at the same time opens the guard circuit of the motor relay 610 to the switch contacts
653. By triggering relay 610 opens its own guard circuit at armature 646 and opens the circuit of rotating magnet 613 at armature 645. Magnet 613 then trips and closes switch springs 653 If the line leading to this first set of panel contacts is busy, the test contact that meets test contact arm 662 will be found to be ground.

   A circuit is then established again for the motor relay 610 starting from the earth at the test contact by the test contact arm 662, the armature 648 and its rest contact, the switching springs 653 , working springs 654 and by winding relay 610 to the trattery. Relay 610 is energized again and closes the circuit of rotating magnet 613 which begins to act again and advance the contact arms stepwise to engage them on the next set of contacts on the panel. In this way the step relay 610 and the magnet 613 function-
 EMI52.1
 nent alternately until the contact arms are engaged in their rotary motion on a set of panel contacts forming the end of a free line.

   Once an unoccupied line is found, which will be assumed to be the one comprising conductors 65-658 terminating at panel contacts 665'-668 ', contact 666' will not be found to earth and will not be made. therefore - no circuit passing through the step relay 610; the contact arms will therefore stop on this contact set.

  <Desc / Clms Page number 53>

 panel tacts.

   On the other hand, since the lower terminal of switch relay 611 is no longer earthed, this relay is now able to be energized on the following circuit: from earth by trip conductor 555 , the winding of the relay 611, the switch contacts 653, the working springs 654, and by the winding of the stepping relays 610 to the battery. Due to the high resistance of the switching relay 611, the current flow in this circuit is insufficient to actuate the relay 610.

   Switch relay 611 on the other hand attracts its armatures and makes the following circuit changes: test contact 6661 and trip lead 666 are set to the bar via contact arm 662 and the switch. armature 648 with its make contact which is connected with trigger conductor 555, such that the line is marked "not free". A circuit is then closed for the upper winding of switch relay 301 of connector C to which the selected line terminates, and switch relay 301 of connector C is therefore energized on the winding of its first degree to prepare connector C to receive. the first series of pulses as described above. By attracting armatures, relay 611 also prepares the circuit from reversible relay 602 to armature 649.

   At armature 650 a point in the initial circuit of relay 610 is opened in order to prevent that relay from operating in response to the transmission of the next digit. At reinforcements 647 and 652 the connection is extended.

  <Desc / Clms Page number 54>

 ged up to connector C, the connection with the earth and with the battery via the magnet
612 having been cut with the large conversation conductors and replaced by your connection of the earth and the battery with connector C through the vertical magnet 306.

   At armature 651 is closed a circuit which goes from earth through armature 626 and its rest contact, armature 651 and its working contact, contact arm 663, contact 657 'of the panel, the conductor 667 controlling the bell, armature 314 and its normally closed contact, and by the upper winding of the bell cut-off relay 304, and resistor 309 at the battery. Relay 303 attracts its armatures and closes a guard circuit for itself at armature 3191, closes at armature 319 a point of the "not free" acoustic signal circuit and interrupts the circuit at armatures 318 and 320. ringing, closing at the same time certain points of the conversation circuit.



   In response to the next two digits transmitted by the transit operator by means of his dial device, the U connector operates in the same way as that described above and places its contact arms on the set of contacts of the panel to which terminates the line to station A "ie, contacts 344-346 and the line for station An is then probed to determine whether it is busy or free.



  Immediately after the repetitive movement the Switch 301 relay is energized by its second degree winding and by attracting its armatures performs the

  <Desc / Clms Page number 55>

 following operations: the connections of the conversation conductors with the earth and the battery are interrupted by the attraction of the armatures 311 and 315 so that the circuit of the guard relay 608 of the TTS transit transmitter selector is open.



    At armature 314 the bell control conductor 667 is cut from the lower terminal of the bell cut-off relay 303 and is connected to the upper terminal of this winding.



   By tripping, the relay 608 closes certain points of the conversation circuit, allowing the armatures 640 and 642 to make contact with their rest contact. Triggering of armatures 641 opens the circuit of relay 690 and of lamp L1 and closes a circuit for the changeover relay 602 as follows: from earth through armature 641 and its normally closed contact, the opening contact of armature 649 and this armature itself, and by winding the relay 602 to the battery.

   Relay 602 attracts its armatures and performs the following circuit changes: a armature 625 the bell relay 601
 EMI55.1
 Ô ", is connected in bridge on the capacitor 695 in series with the capacitor 696, At the armature 624 is open a point of the initial excitation circuit of the relay 608 and at the armature 622 the grounding of the driver 556 is deleted.

   By the attraction of the armature 623 the current supplied by the battery via the upper coil of the relay 605 is cut off from the conductor 554 and is connected to the conductor 556 via

  <Desc / Clms Page number 56>

 of resistor 617 and the lower left winding of the translating coil R6, At the armature 626 the setting of the control conductor of the bell 667 is removed and this before the relay
303 is de-energized as a result of the attraction of the armature 314 At the same armature the conductor 554 is earthed by the intermediary of the lower winding of the relay 605, the rest contact of the armature
629 and this armature itself, resistor & I8 and the upper left winding of the translating coil R6;

     in this way the direction of current flow is reversed on the rear transit line. The polarized relay 507 now attracts its armatures and closes the circuit of the lamp L4, the ignition of which indicated to the transit operator that the connection has been established with the desired line.



   When the contact arms of the connector are engaged on the contacts to which the line leading to the Air station ends, this line is busy, the "not free" signal relay 304 is actuated in the manner described above, closing a guard circuit for itself, and by the attraction of armature 322 the setting.

   to the intermittent earth is extended by the common switch I, the working contact of the armature 319 and this armature, the armature 322 and its working contact, the working contact of the armature 315 and this armature , the conductor 236, the conductor 668, the contact of the panel 668 'the contact arm 664, the armature 652 and its working contact, the armature 642 and its rest contact, 1? armature 638 and its rest contact, the lower right-hand winding of the translating coil R6 and pa the winding

  <Desc / Clms Page number 57>

 bottom of the battery current distributor relay 603 to the battery.

   The result is that the relias 603 is alternately energized and de-energized and each time opens and closes the circuit of the relay 604, The relay 604 attracts its armatures 628 and 629 in such a way as to open or close the circuit of the relay intermittently. larisé 507 of. DC circuit to the cord, so that intermittent opening and closing of the L4 lamp circuit causes the lamp to flicker. The flickering of the L4 lamp warns the operator that the requested line is busy and she will then remove the P 4 plug from the J jack to trigger the connection.



   On the contrary, it will be assumed that the line at station A "is not occupied when connector 0 places its contact arms on the panel contacts to which this line terminates. In this case the" not free "relay
4 304 is not activated and the lamp L of the operator's DC cord remains on continuously to let the operator know that the line terminating at station A "up to which the communication has been established is free at that time.



   After having been informed that the communication has been carried out to the desired station, and that the line leading to this station is at this time free, the telephone operator of the transit office, as soon as ready, places the K 'key in the position bell and thus connects alternating current to the line conductors. In response to this alternating current, the bell relay 601 attracts its armature and extends the earthing through the trigger conductor 555 which is at the ground. earth by

  <Desc / Clms Page number 58>

 the working contact of the armature 621 and this armature itself, the armature 630 and its rest contact, the armature 651 and its working contact, the contact arm 663, the contact 657;

   of the panel, the conductor 667, the frame
314 and its normally open contact, up to the upper terminal of the bell disconnection relay 305. The relay 305 is thus short-circuited, abandons its armatures and completes the bell circuit to activate the bell. stamps at station A ", The bells ringing at station A" will then ring intermittently until the subscriber answers the call.



   When the subscriber of station A "picks up his receiver to answer the call, a direct current bridge is connected to the line conductors 371-372 and actuates the switch-off relay 303 in the manner previously described. The attraction of the openings 318 and 320 opens the ringing circuit and closes a circuit for the current distributor relay of the battery 603, This circuit comprises the upper and lower conversation conductors and the series line conductors of the called station. ., Relay 603 attracts its armature and closes a circuit cooked for relay 604.

   Relay 604 attracts its armature and interrupts the battery and ground connections with conductors 554 and 556 thereby opening the bias relay circuit 507 of the transit telephone DC cord circuit. The polarized relay 502 consequently releases its armatures and interrupts the circuit of the lamp L4. Switching off the L4 lamp warns the transit operator that the called subscriber has answered the call.

  <Desc / Clms Page number 59>

 



   The forwarding operator at the main transit panel then informs the forwarding operator at the remote office that communication with the called subscriber is established. The remote transit operator then establishes the final connection and the calling subscriber, who initiated the call in transit, as well as the called subscriber can initiate their conversation.



     Instead of the conversation, the calling subscriber and the called subscriber will both hang up their respective receivers. When the subscriber of station A "puts his receiver back in place, the bridge on line conductors 371 and 372 is open, interrupting the circuit of the battery current distributor relay 603. This relay 603 de-energizes and opens the relay circuit. 604. Relay 604 de-energizes and reconnects battery and earth to conductors 556 and 554 which again operates polarized relay 507 of the DC cord circuit of the transit office telephone operator and causes it to close the circuit. of the L4 lamp The switching on of the L4 lamp warns the forwarding telephone operator that the subscriber at set A "has hung up his receiver.

   It then removes plug P 'from jack J and gives the operator at the remote transit office the signal to disconnect by any suitable means, for example by operating the K key and then plugging in alternating current on the conductors. not shown in the incoming line.



   The removal of the P 'plug of the jack I open the circuit of the line relay 605 of the TTS transit selector transmitter by opening the bridge on the conductors of

  <Desc / Clms Page number 60>

 line 501 and 502, whereupon relay 605 is de-energized and lets its reinforcements fall back to their normal position.



   The armature 631, by coming to rest against its rest contact, puts the winding of the trip relay 606 in bypass and causes it to trip soon after, so that its armatures are returned to their normal position.



   Relay 609 is momentarily energized while armature 631 is tripped and relay 606 energized, but its energization is not used this time. Following the return of relay 606 to its normal position, the grounding of the trip conductor 556 to the armature 633 is suspended which determines the tripping of the selector S and also of the connector C.

   The tripping of connector C has been described previously and the operation of tripping the selector S is well known, so that a detailed description of the tripping of these switches is deemed unnecessary. Trigger 555 also opens the TTS transit transmitter selector switch relay circuit, such. so that this relay is de-energized and allows its reinforcements to resume their normal position. The return of the armature 649 to its normal position simultaneously opens the circuit of the changeover relay 603 which is de-energized thereon and returns its armatures to their normal position. Another effect of returning relay 606 to its normal position is closing the circuit for trip magnet 614.

   This circuit goes from the earth through the rest contact of the armature 634 and this armature itself, the working springs 655 which closed at the first vertical step of the control arms.

  <Desc / Clms Page number 61>

 tact, and by winding the trigger magnet 614 to the battery. Trigger magnet 614 is energized and returns the contact arms in the usual manner to their normal position. All devices used in establishing the transit connection from the transfer panel to the subscriber of station A "are thus brought back to their normal position and are ready to be used to establish a new connection.



   The telephone system which has just been described also allows calls to be made to a private secondary office over any one of a group of lines by telegraphing by means of the rotary device the number assigned to the desired secondary office. Lines terminating at private sub-offices are accessible through rotary connector contact panels such as the RC rotary connector shown in fig. 8. which are accessible, in turn, to tertiary selectors and local transmission selectors. This rotary connector is modified so as to work satisfactorily in combination with the rest of the switches used in the system considered.

   To describe the operations performed by this apparatus in establishing communication with a private sub-office, it will be assumed that the subscriber of station A wishes to communicate with private sub-office X (place the drawings in order shown in fig.ll.)
To establish a communication with the private secondary office X, the subscriber of station A picks up his receiver again and transmits, by means of his dial, the call number assigned to the secondary office X.

  <Desc / Clms Page number 62>

 removal of the receiver and transmission of the first three digits of the called number * the line switch starts looking for a free primary translator selector and establishes the connection with it;

   this primary translator selector will again be assumed to be the SR selector which then begins to search for a free local secondary selector, the selector S 2 for example, and to establish the connection with it. This secondary selector chooses to choose a local tertiary selector which is free, to connect with it, for example the selector
8 /, and the local tertiary selector starts to choose an unoccupied rotary connector and to establish its connection with it (the rotary connectors being accessible to a determined stage of the contact panels of these selectors). It will be assumed that the chosen connector is the R C connector.



   By taking possession of the line comprising the conductors 854 -857, the tripping conductor 855 is earthed which causes the excitation of the two-degree relay 801 in the first degree, and consequently, the opening of At a point in the circuit from the trip magnet 810 to the armature 812, at the same time a circuit is established going from the earth of the trip conductor 855 by the working springs 840 which opened at the first. - place the contact arms vertically, and through the lower coil of the 807 switch relay to the battery.



  Relay 807 which now acts as a switching relay, attracting its armatures establishes a protective circuit for itself at armature 834 and disconnects at armature 833 the rotating magnet 809. while vertical link 808 is connected, in series with the relay

  <Desc / Clms Page number 63>

 series 804, on the lower conversation conductor via armature 815 and its rest contact v The attraction of the rest of the armatures of relay 807 has no effect this time.



   In response to the transmission of the next digit, the Vertical magnet 808 will operate to lift the contact arms 841 # 844 at the contact stage of the contact panel corresponding to the digit 'notched. The relay 804 is energized in series with the magnet 808 and, being delayed tripping, is kept closed continuously during the transmission of the pulses. The pull of the armature 822 closes the circuit of the delayed action relay 805 which, when energized, keeps the guard circuit of the relay 807 closed at the armature 826; this circuit includes armature 834.

   The circuit on which this relay is initially energized is interrupted at the vertical working springs 840 at the first vertical step of the contact arms, At the end of this series of pulses, the relays 804 and 805 trigger and the guard circuit of the relay 807 is interrupted.

   The relay 807 is de-energized and by releasing its armature 833 couples the rotary magnet 809 again in series with the relay 805,
In response to the last set of pulses, the rotating magnet 809 begins to operate and rotates the contact arms 841--844 to engage them with the contact set of the contact panel to which the first row terminates. of the group of lines going to the private secondary office X., During the transmission of this series of pulses the relays 804 and 805 functioning again, the relay 805 preparing for its armature 824 and the contact of

  <Desc / Clms Page number 64>

 working of this one circuit for the relay 0 * 'test 806 being used to know if the line is occupied or not.



   The operation of the connector R C following the supply of the contact arms 841-843 on the contacts to which the first line of the group going to the private secondary office X ends depends on the occupied or free state of this line at that moment. It will be assumed that the first line of the group is the one that leads to contacts 845 -
848 and that the last line of the same group is the one ending at contacts 845'- 848't.



   If the first line is busy at this time, contact 846 will be grounded and contact 848 connected with it through the closing wire.
849. It should be noted that the test contacts similar to contacts 846 and 848, for all the other lines of the group, except the last one, are linked together by means of closing wires similar to the closing wire. 849.



  As soon as the contact arm 842 engages the test contact 846 a circuit is established from the earth of the contact 846 by the contact arm 842, the armature 824 and its working contact, the NC contact of armature 832 and this armature itself, and by winding test relay 806 to the battery. Relay 806 draws its armatures and opens, at armature 827 a point in the circuit for the repeating bell, prepares armature 828 for a guard circuit for itself, and, at armature - Tures 829 a circuit for the motor relay 803 with stepping advance, and, at the armature 827 'prepares the circuit for the "not free" signal.

   At the end of this last series of pulses, the relay 804 trips and by leaving the armature 822 prepares a guard circuit for the.

  <Desc / Clms Page number 65>

 auxiliary series relay 805, and closes, armature 823 a circuit for motor relay 803 This last circuit goes from the ground of test contact 848 through contact arm 844, armature 829 and its make contact , the armature 825 and its make contact, the armature 823 and its rest contact, the switch springs 836 and by winding the motor relay 803 to the battery The relay 803 attracts its armatures and germs.,

     to the armature 821 a guard circuit for itself going from the ground of the tripping conductor 855 through the rotating working springs 839 which closed at the first rotary pitch of the contact arms, the contact of work of the armature 821 and this armature, the switch contacts 836 and by the winding of the relay 803 to the battery. At armature 820 are closed the excitation circuit for the rotary magnet 809 and the guard circuit for the relay 805.

   These circuits are as follows: from earth through tripping conductor 855, rotating working springs 839, arma-. ture 820 and its make contact, thence by the rest contact of armature 822 and this armature itself, and by the winding of relay 805 to the battery, and also by the normally closed springs commanded by lar- mature 833 and by winding the rotating magnet 809 to the battery. Relay 804 therefore remains energized and magnet 809 rotates the contact arms to bring them to the next set of contacts simultaneously opening the circuit from the motor relay to the switching springs 836, Relay 803 trips, thus opening its own circuit, guard at armature 821 and, at armature 820, the circuit for relay 805 and magnet 809.

   Lover 809 triggers

  <Desc / Clms Page number 66>

 then and closes the switch springs 836.



   If the line accessible to this next set of contacts on the panel is also busy, earth will again be encountered at both contacts of the. panel that correspond to contacts 846 and 848. Relay 803 will energize again and close a circuit for magnet 809 as a result of movement of the arms. switch which engages these on the next set of contacts on the contact panel.



   In this way the contact arms will be advanced step by step in their rotary movement until they meet a free line or until they are engaged on the contacts 845 '-847 to which ends. the last line of the group of lines leading to the desired private secondary office.



   Assuming that the contact arms 841-843 have been engaged on the contact pads to which the last of the lines in the group ends, all the others having been recognized as busy, and that this last line is then occupied or not, it will not be in No circuit case established for motor relay 803, since panel contact 848 'is not connected to contact 846' and the contact arms will therefore remain stopped in this position. If this line is also busy, test relay 806 remains energized.

   Relay 805, which had been kept energized for the duration of the switch requesting movement due to the fact that a circuit is closed for it each time armature 820 is drawn, trips, no longer being energized and closes a guard circuit for the test relay

  <Desc / Clms Page number 67>

 806 This circuit extends from the ground of the tripping conductor 855, through the armature 828 and its work contact, the normally closed springs that control the armature 824, the rest contact of the armature 832 and this armature and by winding the test relay 806 to the battery.

   The triggering of the armaturen826 closes a circuit going from the earth through the tripping conductor 855 the rotating working springs 829 the armature 826 and its rest contact, the working springs 837 which are closed at the first vertical pitch of the contact arm, and through the lower winding of the two-degree relay 801 to the battery. The relay 801 is energized on its second winding, interrupts to the armatures 811 and 815 the normal connections of the upper and lower conversation conductors with the earth and the battery through the relay 804 and the magnet 809. and opens. the circuit of its own initial energizing winding to armature 814. The attraction of armature 813 has no effect this time.

   These operations determine certain others to the primary translator selector described in combination with the establishment of a previous connection, resulting in the closing of a conversation circuit starting from the calling station at connector R C. The armature 815 of the relay 801 of the RC connector, leaning against its working contact, at the same time closes the circuit of the "not free" signal from the machine emitting this signal. This circuit is as follows; from the conductor 891 by the ammature 819 and its rest contact, the working contact of the frame 8271 was this frame itself, the working contact of the frame 815 and the latter itself, the working contact of the frame 815 and the latter herself

  <Desc / Clms Page number 68>

 to the lower conversation conductor.

   The "not free" signal is then transmitted to the calling subscriber to inform him that all the lines for the desired secondary office are busy.



   It will now be assumed that the last line in the group leading to the requested private sub-office is found free when the RC rotary connector engages its contact arms 841-843 on contacts 845'-848. '' of the contact panel to which this line terminates There will be no earth potential at the contact
846 'of the panel, and the test relay 806 will therefore be instantly de-energized as soon as the contact arm 842 engages the fixed contact 846'.

   When the relay 805 releases its armatures, the relay 801 is energized in this case as explained above and closes a circuit going from the earth through the tripping conductor 855, the armature 828 and its rest contact. , through the upper winding of the switching relay 807, the rest contact of the armature 824 and this armature itself, the contact arm 842, the fixed contact 846t and through the winding of the motor relay 861 of the individual line switch LS of the chosen line, the switch contacts 869 and by the winding of the rotating magnet 863 to the battery.

   Relays 807 and 861 are energized on this circuit, but due to the relatively considerable resistance of relay 861 the current in this circuit is not sufficient to determine the operation of magnet 863, due to the interlock device. mechanical between relays 861 and 862, relay 861 can only interrupt the normal connections of the line conductors with the earth and the battery by relay 862, Relay 807 by drawing its armatures makes the following changes of the circuits: With frame 831 and its

  <Desc / Clms Page number 69>

 make contact fixed panel contact 846 and contact arm 842 are grounded to signal this line as busy.

   At armature 834 is closed a guard circuit for relay 807 going from earth through tripping conductor 855 the rotating working springs 839 armature 834 and its working contact, and through the lower winding of relay 807 to the battery. To armatures 830 and 835 is closed the signaling circuit which goes from the earth through the rest contact of armature 816 and this armature, armature 830 and its work contact, contact arm 841, contact fixed 845 ', the line conductor 881, the contacts 844, the winding of the control magnet 880 of the indicator light, the contacts 883, the line conductor 882, the contact 847' of the panel, the contact arm 843, the working contact of the armature 835 and this armature itself, the armature 819 and its rest contact,

   the lower winding of the bell cutout relay 802 to conductor 890 connected with the regular bell conductor 350. The bell current flowing in this circuit drives annunciator 886.



   The operation of this indicator light warns the telephone operator of the private sub-office of incoming calls, and the latter will then answer the call by inserting the plug of a single cord into the J8 jack.



  By this operation, it opens the signaling circuit by separating the contacts 883 and 884 and at the same time establishes a direct current bridge on the line conductors 881 and 882. Oe direct current bridge

  <Desc / Clms Page number 70>

 established astride the line conductors determines the excitation of the bell cut-out relay 802 in the usual manner. This relay 802 by attracting its armatures closes to armature 818 a guard circuit for the third core and finally completes the conversation circuit to armatures 816 and 817 and their respective working contacts.

   The other maneuvers performed by the operator of the private secondary office which are necessary to send the call to the called subscriber are well known and do not form part of the object of this invention, they are therefore not ex - plied in the present description.



   Once the communication has been established between the calling subscriber and the one he called, the two subscribers can initiate their conversation and at the end of this conversation the two subscribers will hang up their receivers. The operations carried out by the primary translator selector,

   the secondary selector and the tertiary selector by tripping have been described previously and since the triggering operations of the R C connector are identical to those of the C connector, no new description of these operations will be given.
In any telephone system, devices are generally provided for serving groups of subscribers. In the present system the lines which serve several subscribers terminate at the central at individual line switches which are identical to the line switches which terminate individual subscriber lines, and are accessible to the contact panels of a group. of connectors.

  <Desc / Clms Page number 71>

 frequency selectors, such as connector F S C fig.

   7 which has been modified to operate in combination with the rest of the apparatuses adapted to the needs of the invention.



   In the above description, the operation of the primary selector-translator S R fig. 1 which has been designed to be used to establish connections from subscriber stations, the subscriber meters which are actuated by means of a fourth conductor going from the primary translator selector by the individual line switch to the subscriber counter. born.

   Another common method of ensuring the operation of a subscriber's meter is to momentarily apply the current of an auxiliary battery to the trip lead, the subscriber's meter being in this case set to limits. data and connected directly with the trip conductor or conductor deprived of rest The primary translator selector SR '(fig. 9) whose main circuits and operation are similar to those of the primary translator selector SR shown in fig. 1 is therefore suitable for use in establishing connections from subscriber stations whose meters must be actuated by the momentary application of an auxiliary battery current to the tripping conductor.



   To describe the operations carried out by a primary translator selector of the alternative type such as the selector translator S R (fig. 9) and, at the same time, the operations carried out by a connector

  <Desc / Clms Page number 72>

 frequency selector, such as the F S C connector shown in fig. 7, it will be assumed that the subscriber of the station
B6 wishes to establish a communication with a subscriber at station A6 (assemble the drawings according to fig. 12).



   To establish this communication, the subscriber of set B6 picks up his receiver and transmits by means of his dial the call number of the desired subscriber. In response to the removal of the receiver at station B6, the line switch L S9 which is individual to the line to which the conductors 901 and 903 belong begs to connect with a free primary switch selector which is either accessible to the contact panel of said switch. It will be assumed that it is the primary translator selector S R 'which has been chosen.



  As soon as communication is established with this translator selector, a circuit is closed for the line relay 926 comprising the two line conductors 901 and 903 as well as the line conductors 921 and 924 in series. The line relay 926 by drawing its armatures prepares the armature 943 a circuit for the repeater relay for connecting the battery and closes, at the armature 942 a circuit for the trip relay 927.

   The 927 trip relay by attracting its armatures makes the following circuit changes: At armature 944 the trip conductor 922 is earthed which marks the line leading to this primary translator selector S And as occupied and additionally complete the guard circuit for switch relay 907 of the line switch

  <Desc / Clms Page number 73>

 L S9, this operation taking place before relay 906 which is delayed action has time to release its armatures.

   At armature 947 is prepared a circuit for relay 929 series. At armature 945 and 946 is closed an initial excitation circuit for guard relay 928. This circuit is as follows; earth by armature 955 'and its normally closed contact, armature 950 and its closed contact, the working contact of armature 945 and this armature itself the normally closed springs controlled by armature 962 , armature 960 and its rest contact, armature 946 and its work contact, resistor 936 the lower winding of relay 928, armature 958 and its rest contact, the rest fontact of the armature 941 and this armature, the normally closed springs controlled by the armature 964, and by the winding of the vertical magnet 933 to the battery.

   Relay 928 attracts its armatures and closes, to armatures 948 and 952 a new circuit for its lower winding which goes from the earth by the normally closed springs that control armature 961, armature 937 and its contact of rest, armature 948 and its make contact, armature 946 and its work contact, resistor 963, the lower coil of relay 928, the make contact of armature 952 and this armature the contact rest of the armature 941 and this armature, the normally closed springs controlled by the armature 964 and by the winding of the vertical magnet 933 to the battery. In frame 950 a circuit for control relay 981 is closed, the function of which will be described later.

   At the ar-

  <Desc / Clms Page number 74>

 Mature 949 is prepared a guard circuit for the upper winding of relay 928.



   The translator selector S RI is now in a state to receive the first series of pulses to be transmitted by the subscriber who calls by means of his dial device, all the above operations having taken place in response to the receiver going off hook. calling station. In addition, as soon as the contact arms of the line switch L S9 have been brought by their rotation onto the contacts of their contact panel to which the line leading to the primary translator selector S R 'ends, a circuit for the warning signal call is closed., This circuit goes from conductor 993 connected with the machine for the call warning signal by vertical working springs 997 which are normally closed,

   to the lower conversation conductor from where. the accustic call signal is transmitted to the calling subscriber. Receipt of this signal indicates to this subscriber that he can begin to transmit by means of his rotary apparatus the number of the desired subscriber.



   In response to the transmission of the first digit of the requested number, the relay 928 and the resistor 936 are short-circuited a corresponding number of times by the contact of the armature 943 with its normally closed contact each time the relay 926 is de-excited. Shorting resistor 936 and the lower winding of relay 928 increases the strength of the current passing through vertical magnet 933 so that this magnet begins to work to bring the arms of the relay. step by step contact in front of the cotact floor of the panel

  <Desc / Clms Page number 75>

 number of contacts that corresponds to the transmitted number. In addition, each time the 926 relay is de-energized, a circuit is established for the 929 series relay.

   This circuit goes from the earth through the winding of the relay 929, the working contact of the armature 947 and this armature itself the armature 942 and its closed contact, the resistor 994 to the battery, and also, through the winding of the trip relay 927 to the battery. Each time relay 926 is re-energized during pulse transmission, relay 929 is again shorted and therefore acquires the character of a delayed trip relay so that it remains energized. during the transmission of the series of pulses.

   By attracting its armatures, relay 929 closes to armature 955 'a guard circuit for the upper winding of relay 928 and thus directly ensures the continuous excitation of this relay during the time that it is short circuited. At armature 955 is closed the primitive circuit for stepper motor relay 931, this circuit goes from the earth through tripping conductor 922, the working contact of armature 955 and this armature armature 963 and its rest contact, the working springs 966 which have closed at the first vertical pitch of the contact arms, and by rolling the motor relay 931 to the battery.

   The relay 931 is escalated and closes to the armature 960 a guard circuit for itself which goes from earth through the upper winding of the relay 925, the work contact of the armature 945. the springs normally closed what order

  <Desc / Clms Page number 76>

 armature 962, armature 960 and its working contact, switch springs 965, working springs
966 and by winding relay 931 to the battery.



   At armature 959 is further prepared a circuit for the rotating magnet 934. The attraction of armature 955 of relay 929 also closes a circuit for relay 929 'which attracts its armatures and prepares armature 956 for a guard circuit for itself. The attraction of the armature 957 actuates, in addition to this armature itself, the springs that the armature 954 controls in the grounding circuit of the triggering conductor 922. The purpose of this operation will be understood as the description develops.



   At the end of the transmission of this series of pulses, the series 929 relay is de-energized since it is now continuously shorted to armature 942 until the transmission of the series d. 'next impulse
The armature 9551 by tripping opens the temporary guard circuit of the relay 928 and the tripping of the armature 955 causes the closing of the circuit of the rotary magnet 934 which goes from the ground of the tripping conductor 922 by the normally closed springs actuated by armature 955, armature 959 and its make contact and winding of rotating magnet 934 to the battery.

   The magnet 934 starts to operate and by rotating the contact arms engages them on the first set of fixed contacts of the chosen stage of the panel, of contacts and at the same time opens the circuit of relay 931 to res0

  <Desc / Clms Page number 77>

 switch spells 965. The relay 931 triggers and opens the circuit of the rotary magnet 934 which, when triggering, closes the switch springs 965. If the line leading to this set of fixed contacts is occupied, the contacts on which is engaged contact arm 972 will be found to earth, thus closing another circuit for motor relay 931 which being energized closes the circuit of rotary magnet 934, the latter resumes rotating the contact arms and engages them on a new set of panel contacts.

   In this manner which is described in more detail in combination with the operation of the primary translator selector SR, the contact arms 971-973 are brought to the first set of fixed contacts belonging to an unoccupied line and the contact arm. switch relay 932 then goes to work to extend the connection to the secondary selector to which the selected line leads and which performs other operations identical to those performed by the switch relay 132 of the primary transformer selector SR described on 1 occasion of a previous connection O
It will be assumed that the secondary selector S2 accessible to the fixed contacts 974'- 976 'of the panel is the one chosen,

  (being further assumed in the present case that the line to which the conductors 174-176 belong terminates at the fixed contacts 974'-976 ').



   In response to the transmission of the next digit, the secondary selector S2 starts up and chooses a

  <Desc / Clms Page number 78>

 line leading to an unoccupied tertiary selector accessible to 1 * stage of fixed contacts corresponding to the digit transmitted, to extend the connection up to this tertiary selector. It will be assumed that it is the tertiary selector S which has been chosen.

   Selector S3 is therefore activated in response to the third digit transmitted to raise its contact arms to the level of the stationary contact stage belonging to the desired group of frequency selector connectors and to then rotate its contact arms. looking for a line leading to a frequency selector connector available to extend the connection to this connector.

   It will be assumed that the connector chosen is the frequency selector connector F S C. By taking possession of this connector, the conductor; trigger 755 is grounded so that a circuit is established for the top winding of the two degree relay 701 and also. a circuit from the earth of this conductor through the vertical working springs 740 which opened at the first vertical pitch of the contact arms, through the winding of the combination changeover switch relay 704 to the battery.



  The two-stage relay 701 acts only through its armature 713 activated at the first degree of excitation, which opens a point in the circuit of the trip magnets 709 and 744. The relay 704 is energized on the circuit traced below. -d ssus its useful function consisting in this time to connect the vertical magnet 707 through the armature 728 and its working contact

  <Desc / Clms Page number 79>

 normally closed springs actuated by armature 736, of the rest contact of armature 714 and of this armature, with the lower conversation conductor 756.



   In response to the next digit transmitted by the calling subscriber, the vertical magnet 707 is activated to place the contact arms at the height of the stage of fixed contacts corresponding to the digit trans. put. The 705 series relay being coupled in multiple with the magnet 707 and being delayed action, attracts its armatures and remains energized during the entire duration of the transmission of pulses to the vertical magnet 707.



   The useful function this time fulfilled by relay 705 consists in closing a guard circuit for relay 704, a circuit going from the earth through conductor 755, armature 730 and its work contact, the work contact of the armature 725 and this armature and the winding of the relay 704 to the battery. The relay 704 is thus kept energized by this circuit for the duration of the transmission of vertical pulses, its initial circuit being interrupted by the separation of the working contacts 740 by the first vertical step of the contact arms. At the end of this series of pulses, the series relay 705 trips and opens the circuit from relay 704 to armature 730.

   The relay 704 trips and, leaving its armature 728, disconnects the magnet 707 and substitutes the rotary magnet 708.

  <Desc / Clms Page number 80>

 



   In response to the next series of pulses transmitted by the calling subscriber through his dial calling device, magnet 708 turns on to place contact arms 741-743 on the contact set. fixed corresponding to the transmitted digit which are the contacts
744-746 belonging to the line leading to station A6, Relay 705 starts up again, this time multiple with rotating magnet 708, its useful function this time being to prepare for armature 729 and its working contact the circuit for the test relay 702.

   How the FSC connector will act next then depends on whether the line at station A6 is currently busy or free, assuming first that the line at station A6 is busy when the contact arms are engaged. on the fixed contacts 744-746, the fixed contact 745 will be found to the ground, so that a circuit is established from the ground of this fixed contact by the contact arm 742, the armature 729 and its contact of work, the rest contact of the armature 735 and the winding of the test relay 702 to the battery.

   The test relay 702 by drawing armatures makes the following circuit changes: At armature 715 a point in the ring repeater signal circuit is open while a point is closed in the signal circuit. not free ". At armature 716 and its working contact is prepared a guard circuit for relay 702. At armature 717 a point of the initial circuit of relay 706 is opened while at armature 719 a point in the circuit of the lower winding of the two-step relay 701 is closed.

   Shortly after the end of the pulses for the rotary operation of the connector, relay 705 is again de-energized and closes a circuit

  <Desc / Clms Page number 81>

 guard for the test relay 702, This circuit goes from the earth of the conductor 755 through the opening contact of the opening 716 and this armature, the springs normally closed controlled by the armature 729, the rest contact armature 735 and that armature itself, and the coil of relay 702 to the battery. The armature 730 by tripping closes a circuit going from the earth of the conductor 755 by the armature 730 and its normally closed contact, the armature 719 and its make contact, and the lower winding of the two relay. 701 degrees to the battery.

   Relay 701 is energized on its second winding and performs identical circuit changes to those made by similar relays on the other two connectors described previously, the end result being the transmission of the "not free" signal to the relay. subscriber calling to inform him that the requested line is busy.



  * It will now be assumed that the line terminating at station A6 is free when the contact arms 741-743 have engaged in their rotational movement on the fixed contacts 744-746 belonging to this line. annoyance. In this case the relay 702 is not energized. When relay 705 leaves its armatures immediately after the end of the last series of pulses transmitted by the calling subscriber by means of his dial device, a circuit is established going from the ground of the starting conductor. triggering 755 by this conductor, the rest contact of the armature 717 of this armature, the upper winding of the relay 706, the rest contact of the armature 729 and this armature itself, the contact arm 742, the fixed contact 745 of the panel,

   the relay winding

  <Desc / Clms Page number 82>

 switch 761 of the LS line switch. the switch springs 769 and 1 * winding of the rotating magnet
763 to the battery. Relays 706 and 761 are energized on this circuit, but due to the relatively large resistance of relay 761 the current flow in this circuit is insufficient to cause the magnet to be energized.
763. As a result of the usual locking mechanism in addition to relay 761 and relay 762 of the line switch
LS7.Relay 761 armatures can only disconnect line conductors 782 and 781 from their normal earth and battery connections.

   Relay
706 by triggering makes the following circuit changes: The test contact 745 is earthed through the armature 733 and its working contact, so as to indicate that the line at post A is occupied. At armature 734 is closed a guard circuit for relay 706. This circuit runs from earth through trip lead 755, armature 734 and its work contact, and the lower coil of the relay. 706 to the battery. At armature 735, a point in the circuit of test relay 702 is open, serving to recognize the busy or free state of the line. At armatures 732 and 737 are closed points of the conversation and signaling circuit which are normally open.

   The attraction of the armature 736 disconnects the rotating magnet 708 from the conversation conductor 756 and substitutes it for the frequency selector switch magnet 773.



   The last digit of the called number is the digit which determines the frequency of the signaling current to be used, and the line to which it is to be applied.

  <Desc / Clms Page number 83>

 quer, and consequently determines which of the subscribers hranched on the called line to which the signal must be addressed.

   The last digit to be transmitted by means of the dial call device is in this case the digit
6, the posts connected to the line having been numbered by exponents corresponding to the number to designate each pastel In response to the transmission of this number, the magnet 773 is excited BY following the short-circuiting of the resistor 936 and the lower winding of relay 928 of the primary translator selector sR '. and proceed to rotate the frequency selector contact arms 771-772 so as to engage them on the sixth set of contacts of their respective contact boards.



   The last five contacts in the contact arm 772 switch board are multiple connected with earth, therefore, when contact arm 772 is engaged on the sixth contact of its fixed contact group, the circuit for relay 704 is connected. found closed. In this period of the operation of the FSC connector, the function of relay 704 is to determine to which side of the selected line the selected ringing current is to be applied.



   Immediately after the end of this series of pulses, relay 705 is de-energized again and, by tripping, this time closes the circuit for the lower winding of relay 701. This circuit is as follows: From the earth via the conductor trigger 755, armature 730 and its rest contact, working springs
739 which are closed as soon as the selector contact arms 771-772 are moved from their position. rest position via the lower coil of the relay

  <Desc / Clms Page number 84>

 two degrees 701 to the battery.



   The relay 701 is energized by its second winding in the manner described, the end result being the preparation of the primary translator selector circuit SR 'for conversation -, and the transmission of the ringing repeater signal to the calling subscriber., This repeater signal. starting from the conductor 790 connected to one of the conductors of the generator, by the rest contact of the armature 721 and this armature, the rest contact of the armature 715 and this armature, the working contact of the armature 714 and this frame, and from there to conductor 756 from where it is transmitted to the calling subscriber.

   This last triggering of relay 705 again results in the closing of the bell circuit which leaves conductor 796 to which direct battery current and battery current are alternately connected, superimposed on the generator current of the desired frequency, by contact 788, the contact arm 771, the lower winding of the bell cut-off relay 703, the armature 731 and its normally closed contact, the armature- 726 and its working contact, the rest contact of the armature 720 and this armature, the armature 732 and the work contact, the contact arm 741, the fixed contact 744,

   line conductor 781 and the bell of set A6 to earth. This signaling current also flows through the ring tones of sets A7-A10. but these rings are tuned to respond to a signal current of a different frequency than a current supplied to conductor 796. The signal current from

  <Desc / Clms Page number 85>

 driver 796 rings at set A6 to notify the subscriber and this ringing will continue until the subscriber of set A6 answers the call or until the call is canceled by the subscriber whose it emanates.



   As soon as the subscriber at station A6 picks up his receiver to answer the call, a direct current bridge is established across line conductors 781-782 and closes a direct current circuit for the lower winding. of the bell cut-off relay 703. This circuit goes from the battery connected to the common bell conductor 796 by the lower winding of the relay 703 to the conductor 781 by the path traced above, the bridge established at station A6 , the conductor line 782, the fixed contact 746, the contact arm 743, the working contact of the armature 737 and this armature itself, the armature 724 and its rest contact, the contact of the frame 727 and this frame to the ground.

   Bell disarming relay 703 pulls its armatures, disconnecting the bell repeater signal circuit at armature 721 closes a guard circuit for itself at armature 723 and interrupts at armatures 720 and 724 the ringing circuit, and finally completes the conversation communication between the calling and called subscribers.



   The circuit for the supply back-up 430 of the battery current is then closed. This circuit comprises the bridge across the line conductors at the station called A6, the two conversation conductors passing through the switches operated in series the conductors 921 'and 9243'. reinforcements 937 and 941

  <Desc / Clms Page number 86>

 and their normally closed contacts, armatures 948 and 952 and their normally closed contacts, the upper coil of the relay
930 to earth, and by the lower winding of this relay to the battery through the armature 943 and its make contact, and the armature 951, and its break contact.

   Relay 930 attracts its armatures and disconnects at armature 958 the lower terminal of the winding of relay 928 from the lower conversation conductor, opens to armature 953 the circuit of relay 929 'activating the counter, and connects, to the armature 954 and its working contact, the auxiliary battery on the tripping conductor 922 The relay 929 'is delayed tripping and consequently does not de-energize until some time after the opening of the relay. its circuit.

   In this way the tripping conductor 922 momentarily receives current from the auxiliary battery through the armature 954 and its working contact and the armature 957 and its working contact, from the circuit con - tinue by the tripping conductor 922, the contact arm 918, the armature 910 and its working contact, the rest conductor 902 and by the winding of the limited adjustment have 916 from the meter to the central battery, this circuit being complete as long as the two relays 930 and 929 * are energized.



   The magnet 916 then actuates the counter M 'which records the call. Almost immediately after the 929 relay circuit is opened, this relay trips and, by direct aban # giving its armatures, re-earths the con- troller.

  <Desc / Clms Page number 87>

 
 EMI87.1
 trigger driver 922 and causepàen,?! * ïq, 46C release of the set magnet 916,
The calling subscriber and the called subscriber can now initiate a conversation. After the end of the conversation, the two subscribers hang up their receivers and thus trigger the entire call.

   The operations performed by triggering the primary translator selector SR 'are identical to those described above concerning triggering the primary translator selector SE * The operations for triggering the FSC connector are the same as those performed by the C connector whose description has been made above,

   except that in this case the engagement of the armature 713 on its normally closed contact closes a circuit for the trip magnet 744 in addition to closing the circuit for the trip magnet 709. The trigger magnet 709 begins to operate to return the contact arms 741 # 743 to their home position and the trigger magnet 744 begins to operate to return the frequency selector contact arms 771 and 772 to their position. rest.



   Any telephone system comprising lines serving groups of stations, 'must be provided with devices to allow a subscriber to ring another subscriber on the same line, and this preferably without notifying the other subscribers on this line. For this purpose, the described system provides reverse call switches such as the RV reverse call switch shown in FIG. 10. these switches being modified

  <Desc / Clms Page number 88>

 to operate in accordance with the general principles of the invention.

   The operation of a reverse: call switch and that of a primary translator selector to establish a connection with a reverse call switch, as these operations differ from those performed to establish a call. a subscriber not connected to the same line with the calling subscriber will now be described. For this purpose, it will be assumed that the subscriber of set B6 wishes to talk to the subscriber of set B2, (For this description it suffices to refer to fig. 9 and 10, fig. 10 being placed to the right of fig. 9).



   So that the subscriber to set B2 can be called on his telephone, and the subscriber to set B6 can be notified as necessary when the subscriber of set B 2 picks up his receiver, the subscriber of the set must pick up its receiver and transmit by means of its dial device. a special number, which will result in establishing a connection with a call reversing switch and, subsequently, with a special ringing repeater device which will cause the bells of the two subscribers to ring alternately as soon as the subscriber of set B6 hangs up his receiver, the ringing ceasing at set B6 as soon as the subscriber of set B2 picks up his.

   The subscriber to set B6 can then pick up his receiver in turn and talk to the subscriber born from set B2,
The operations performed are as follows:
In response to the removal of the receiver at station B, the line switch LS9 begins to choose a free primary translator selector, which will be assumed to be the primary translator selector SR '.

  <Desc / Clms Page number 89>

 first digit transmitted by the call dial of the calling subscriber, the senator SR 'brings his contact arms in front of the stationary contact stage of his contact panel which gives access to the call reversing switches, and then executes an auto search movement. matic to choose one of these call reversing switches which is free and extend the connection to this switch.

   All these operations are carried out in a manner similar to that in which an unoccupied local sub-selector had been chosen and the communication established with it. It will be assumed that the RV reverse call switch has been chosen. By taking possession of the call reversing switch, the trigger conductor 95 is earthed, thus closing the circuit for the combination reversing switch relay 11; this circuit goes from earth through the trigger conductor 95i, the working springs 57 and the coil of the relay 11 to the battery.

   The relay 11 by attracting its armatures prepares the armature 39 a guard circuit for itself and connects the vertical magnet 17 to the large lower control conductor 96 through the make contact of the armature 40 and this armature itself, the rest contact of armature 32 and this armature, the rest contact of armature 23 and by this: armature itself 0 Another circuit has been closed at the same time since the earth by the tripping conductor 95. the armature 42 and its rest contact, and by the winding of the trip relay 7 to the battery.

   The relay 7 by attracting its armatures opens to the armature 27 a point) of the

  <Desc / Clms Page number 90>

 the trigger magnet and prepare circuits which will be described later,
In response to the second digit transmitted by the app. After dialing the calling subscriber, the vertical magnet 17 begins to operate to place the contact arms 61-64 in front of the stage of fixed contacts corresponding to the digit transmitted. The delayed action relay 13 is energized in parallel with the magnet 17 and, because of its nature as a delay relay, maintains its armatures attracted without interruption during the transmission of pulses to the magnet.
17.

   The relay 13 this time closes the armature 46 a guard circuit for the relay 11, the initial excitation circuit for this relay 11 being interrupted by the separation of the working springs 57 at the first vertical pitch of the control arms. contact. At the end of this series of pulses, the relay 13 is de-energized and by giving up its armatures opens to the armature 46 the guard circuit of the relay 11.



  This relay is then switched off and disconnects from the armature 40 the vertical magnet 17 of the large lower control conductor by replacing it with the rotary magnet 19 by binding its armature 40 to rest against its contact of rest.



   In response to the third digit transmitted by the calling subscriber, the rotating magnet 18 begins to rotate the contact arms 61-64 to engage them on the set of fixed contacts corresponding to the transmitted digit, the contacts 81-84 in the present case.

   Relay 13 is energized again, this time in parallel with magnet 18, and keeps its armatures attracted :, during the whole

  <Desc / Clms Page number 91>

 time that the transmission of impulses to the magnet 18 lasts, By attracting its armatures, the relay 13 this time keeps the excitation circuit of the relay 12 open to the armature 48 and also maintains open points of the circuits for the relays 11 and 15 to the frames 46 and 47 during the rotary movement of the switch, thus preventing the last two relays from operating unnecessarily while the contact arms 61 and 62 engage on contacts before coming to a stop.



     At the end of the transmission of pulses to the magnet 18, the relay 13 is switched off and prepares, at the armatures 46 and 47, the respective circuits for the relays 11 and 15, and closes the excitation circuit for the relay 12 which goes from earth through the lower winding of the relay 12, the armature 45 and its normally closed contact, the armature 48 and its idle contact to the conductor 90 on which are connected in the manner explained further away alternately the current of the battery superimposed on the potential of the buzzer, or the direct current of the battery.



  The relay 12 is energized and closes a guard circuit for its upper winding going from earth through the working contact of the armature 26 and this armature, the armature 44 and its working contact by the upper winding of the relay 12 to the battery. Its initial excitation circuit is cut off at armature 45 and at armature 43 an auxiliary circuit is prepared for tripping relay 7.

   The armature 42 by abandoning its normally closed contact opens the initial circuit for the trip relay

  <Desc / Clms Page number 92>

 
7 and * by coming to rest against its work contact, this armature closes a circuit for the relay 14 which goes from the earth through the tripping conductor 95, the armature 42 and its work contact, the normally closed springs commanded by the armature 29, the winding of the relay 14 and to the battery, the earthing of the conductor 95 being effected this time by the intermediary of the upper winding of the relay 25, the winding,

  The upper element of relay 925 has a sufficiently low resistance so that this relay is not energized when it is connected in series with the switching relay 932 and the following switching relays which are connected in multiple with the trip conductor and excited via relay 925 in the case of a communication between stations not served by the same line.



   However, the resistance of relay 14 of the inverter inverter switch RV is also relatively low and passes through the circuit which has just been drawn and comprising the upper winding of relay 925 and the winding of relay 14 in series, sufficiently of current to determine the excitation of both relay 14 and relay 925. By attracting its armatures, relay 14 prepares a circuit for the lower winding of the switch relay 8 at armature 49 and closes, at armature 50 a auxiliary circuit for relay 7 before the latter has had time to trigger and drop its armatures. as a result of the interruption of its original excitation circuit at armature 42.

   Lower winding of relay 8 n '

  <Desc / Clms Page number 93>

 is not energized this time since it is shunted by the earthing of the tripping conductor through the intermediary of the upper winding of relay 925. Relay 925, on the contrary, performs, when energized, the changes. - following circuit arrangements: The conversion conductors 921 and 924 are connected directly with the conductors 921 and 924 'the capacitors being disconnected, as well as the winding of the relay 926, from their position in bridge on these conductors, by the separation of the normally closed springs controlled by the reinforcements 927 and 941.



  In the circuit of the trip magnet 935 a point is opened at the armature 938. At the armature 939 is prepared a guard circuit for the lower winding of the relay 935 and the closing of the springs 940 is established. connection whereby the trigger lead 922 will later be grounded to the trigger lead 95.



  The relay 926 being switched off triggers and abandons its armatures. The armature 942, coming to rest against its rest contact, connects the battery via the resistor 994 to the lower terminal of the trip relay 927 which is thus put into bypass and therefore trips. By tripping the armature 945 the grounding of the tripping conductor 95 via the upper winding of the relay 925 is removed.



  This operation removes the short-circuiting of relay 8 and enables this relay to be energized on the following circuit. Earthed by armature 24 and its contact to rest the lower winding of relay 8, the working contact of armature 49 and this armature itself

  <Desc / Clms Page number 94>

 and by winding the relay 14 to the battery.

   The earthing of the tripping conductor 95 to lock relays 925 and 932 of the translator selector SR 'and the relay 917 of the line switch LS9 actuated by means of the armature 24 and its contact of the rest, is effected at this moment by the lower winding of the relay 8, the working contact of the armature 49 and this armature, the normally closed springs controlled by the armature 29, and the working contact of the armature 42 and this armature itself, But as soon as the relay 8 attracts its armatures, the tripping conductor 95 is earthed directly through the working contact of the armature 25 and this armature itself , the frame 29 and its working contact and the working contact of the frame 42 and this frame itself.

   By pulling its armatures, the relay 8 still closes the armature 30 a guard circuit to lock itself with the tripping conductor 95, and connects, to the armatures 28 and 32, the upper winding and the. lower winding of the battery power supply relay 6 in bridge on conductors 94 and 96.



   All these operations which have just been explained and which follow the transmission of the last digit of the call number take place in a relatively short period of time, so that the subscriber to set B6 does not have to. not had time to hang up his receiver and that the direct current bridge is still maintained on line conductors 901 and 903.



   As soon as relay 6 is plugged in on conductors 94 and 96, it is therefore energized on

  <Desc / Clms Page number 95>

 call loop comprising line conductors 901 and 903 in series, and closes an auxiliary circuit for the relay, trigger 7 to armature 24 and its make contact, The separation of armature 24 from its con - rest tact opens the circuit comprising the lower winding of relays 8 and 14 in series ât determines the switching off of relay 14. By triggering relay 14 opens to armature 50 a point of an auxiliary circuit of relay 7, but this relay is now energized on the auxiliary circuit comprising the armature 24 and its working contact.

   It should be noted that during the small interval between the closing of relay 8 and that of relay 6 a circuit is closed for relay 5, but this relay is delayed action, as indicated by the solid part in black at the end. upper core, and does not act this time.



   After having completed the transmission of the three digits, the subscriber of set B6 hangs up his receiver and thus opens the bridge on line conductors 901 and 903, consequently cutting off the circuit of the battery 6 current supply relay. This relay 6 by triggering, closes the circuit of relay 5 which goes from the earth through armature 24 and its rest contact, armature 27 and its working contact, the working contact of armature 31, and this armature , armature 36 and its rest contact, and the winding of relay 5 to the battery.



   Relay 5 attracts its armatures and closes L- armature 22 and its normally closed contact another circuit for trip relay 7. This circuit goes from earth.

  <Desc / Clms Page number 96>

 by the working contact of the armature 43. and this armature the rest contact of the armature 34 and the latter armature, the armature 22 and its working contact and the winding of the relay 7 to the drums. In items 21 and 23 are prepared the circuits to warn the two subscribers.



   In this regard, it may be useful to describe in general terms the method to be employed for optionally ringing the calling and called subscribers. The Bt-B5 stations can be ringed by the application of a ringing potential supplied respectively by G'- G5 generators to the line conductor 903, while the B6- B10 stations can be rung by 1 application of a ringing potential supplied to the conductor 901 of the line respectively by the generators G'-G5. To activate the bell at station B2 and also the bell at station B6, the bell potential of generator G2 must be applied to conductor 903 of the line, and the potential of generator G 'to conductor 901 of the line.

   To perform this operation by the call reversing switch RB, the contact arms 61-64 have been brought on the contacts of the contact set 81- 84, The contacts 81 and 82 are connected to each other with the common conductor 71 which is periodically earthed by the arm 85 of the switch I, which is driven in a continuous rotational movement. Each time the conductor 71 is earthed, a circuit for the

  <Desc / Clms Page number 97>

 relay 11 is consequently closed by means of the fixed contact 81 and by the contact arm 61, the rest contact of the armature 46 and this armature, and by the winding of the relay 11 to the battery.

   On the other hand a circuit is closed for the relay 15 via the fixed contact 82, the contact arm 62, the rest contact of the armature 47 and the winding of the relay 15 to the battery. . The contact arm 86 of the switch I is fixed on the same axis as the contact arm 85 and closes a circuit for the switch relay 74 for a determined time if the conductor 71 is not earthed, and again for a certain period of time when this conductor 71 is earthed. The relay 74 'therefore connects the generators superimposed on the battery to the common ringing conductors 72, 73 .. for a certain time during the period when the relays 11 and 15 are energized, and then again for a certain time for a period of time. the period when relays 15 and 11 are triggered.

   Consequently when the relays 11 and 15 are de-energized and the relay 74 is energized, a circuit can be drawn from the generator G 'superimposed on the battery, by the working contact of the armature 91 and this armature. , the common ringing conductor 72, the fixed contact 84, the contact arm 64, the rest contact of the armature 51 and this armature, the conductor 90.

   the rest contact of the frame 35 and this armature by the contact switch relay 10, the rest contact of the armature 38 and this armature, the work contact of the armature 21 and

  <Desc / Clms Page number 98>

 this armature itself, the conductor 96, the fixed contact 974 ', the contact arm 971, the armature 961 and its work contact, the armature 937 and its work contact, the conductor 921 the control arm. contact 917, the make contact of armature 909 and this armature, the line conductor
901 and by the ringing of extension B6 to the ground.

   During the time which elapses between the closing of the switch relay 74 and that of the relays 11 and 15, a circuit is established from the generator G2 superimposed on the battery by the working contact.
2 of the armature Q and this armature, the common ringing conductor 73 the fixed contact 83, the contact arm 63, the working contact of the armature 51 and this armature, the conductor 90. the rest contact of the 'armature 35 and this armature, through the switching off control relay 10, the working contact of the armature 41 and this armature, the working contact of the armature 23 and this armature, the contact working of the armature 23 and this armature, the conductor 96, the fixed contact 976 '.

   the contact arm 973 the armature 964 and its working contact, the armature 941 and its working contact, the conductor 924, the contact arm 920, the working contact of the armature 912 and this armature, the line conductor 903 and by the bell of extension B2 to earth.



   It goes without saying of course that there is also ringing current which passes through the other earthed rings to other stations, but the other rings are tuned in each individual case so as not to respond to the frequency. special ringing current then supplied to the line conductors. The ringing tones of set B2 and set B6 will then be activated alternately until the subscriber of set B2 picks up his receiver to answer the call (or until the subscriber of set B6 picks up the receiver. its receiver momentarily to cancel the call, as will be explained later).

  <Desc / Clms Page number 99>

 



   When the subscriber at set B2 picks up his receiver, a direct current bridge is established on line conductors 901 and 903 and thus closes a direct current circuit for the switch-off control relay 10. This circuit which includes the two conductors of the line and the point of substation B2 in series, goes from the direct battery or from the superposed generator to the battery connected to one or the other of the conductors 72 or 73, by one or the other of the bell circuits described according to the particular moment at which the receiver is off-hook at station B2, to return to the other bell circuit earthed by the armature 38 and its working contact or the 'frame 41 and its rest contact, as the case may be.

   The relay 10 reacts immediately and closes an earth circuit to the armature 37 through the working contact of the armature 43 and this armature, the working contact of the armature 37 and this armature, and by winding relay 9 to the battery.



  The relay 9 by attracting its armatures closes a locking circuit for itself on the tripping conductor 75 to the armature 33 and its working contact opens, at the armature 34 the trip relay circuit. 7, interrupts the ringing current at armature 35 and closes the circuit for tripping magnet 19 at armature 36. This last circuit goes from the earth through armature 24 and its rest contact, l 'armature 27 and its working contact, the working contact of the armature 31 and this armature 31, the armature 36 and its con-

  <Desc / Clms Page number 100>

 working tact, the working springs 55 which are closed at the first vertical step of the contact arms and by the winding of the trigger magnet 19 to the battery.

   The trigger magnet 19 is energized and returns the contact arms 61-64 to their rest position. Separation of the armature 36 from its rest contact furthermore opens the circuit of the delay relay 5 which trips after a short interval and reconnects the relay for supplying the battery current to the armatures.
21 and 23 and to their rest contacts again on conductors 94 and 96. Relay 6 attracts its armatures and again closes the circuit for relay 7 to armature 24 and its make contact, and this before that relay 7 has had time to trigger its armatures due to its delayed tripping nature, the circuit on which it had been kept energized having been opened by the separation of armature 34 from its normally closed contact .



   Stopping the ringing at set B6 notifies the subscriber of this set that the subscriber of set B2 has picked up his receiver. The subscriber of set B6 then in turn picks up his receiver and begins the conversation. The two subscribers can then initiate their conservation, the conversation current being supplied by the intermediary of the windings of the battery current supply relay 6.



   At the end of the conversation, the two subscribers will hang up their receiver and thus open the bridge

  <Desc / Clms Page number 101>

 on the line conductors. This maneuver interrupts the circuit of relay 6 which then triggers and opens the circuit of relay 7. Relay 7 triggers and opens the guard circuit for wire 12 at frame 26 and removes the earthing of the relay. trigger conductor 95 to armature 25 thus opening the guard circuits for relays 8 and 9 such that these relays trip and let return their armatures to their rest position.

   The removal of the earthing of the tripping conductor 95 simultaneously determines the disconnection of the relay 11 which allows its armatures to return to their rest position, this relay having been energized following the closing of the springs. work 57 when the contact arms were returned to their rest position by the excitation of the trigger magnet 19.



   Removing the grounding of the tripping conductor 95 opens the guard circuit of relays 932 and 925 of the primary translator selector SR ', and of the switching relay 907 of the line switch LS 9. The relay 932 trips. and lets return its frames to their rest position. The armature 938, by coming to rest against its rest contact, closes a circuit for the triggering magnet 935 which then attracts its armatures and returns the contact arms 971-973 to their rest position. All the devices are now returned to their idle position and are ready to be used when a new connection is established.

  <Desc / Clms Page number 102>

 



   If the subscriber to station B2 had not answered the called party, the subscriber to station B6 would have stopped ringing and would have triggered the switches which had been operated, by momentarily picking up his receiver. Unhooking the receiver at set B6 would obviously produce the same operations aa call reversing switch RV as those caused by unhooking the receiver at set B2, and hanging up the receiver would determine the triggering operations which come from. 'be described.



   In the above description of the establishment of various connections, only the establishment of a connection in transit from the main transfer board to station A "through the selector has been considered. TTS working transmitter fig. 6 and only the regular connector C fig. 3 has been considered, but it goes without saying that connections in transit can also be established for particular sets of lines with grouped sets such as set A6 by the in - via a frequency selector connector, such as the FS C connector fig. 7 and also to secondary offices by means of a rotary connector such as the RC rotary connector fig. 8. The operation of these connectors when they are used for establishing transfer connections is practically the same as for establishing local connections.

   In each case, however., As was explained in detail during the description of the establishment of a transfer connection with the subscriber of the Axis set the relay binds deactivation.

  <Desc / Clms Page number 103>

 bell circuit, such as relay 802 of connector BC, and relay 703 of FSC connector, is energized immediately after possession of the switch, so as to prevent the application of a signal current to the switch. the line connected until the bell relay is unlocked again by restoring the earthing of the bell control conductor, such as conductor 857 of the RC connector and conductor 757 of the FSC connector according to the needs of the maneuver.



   For the establishment of a transfer connection with a private sub-office, this office is generally provided with means to call back the operator of the private sub-office after she has answered the first signal by inserting the reply form. an unoccupied cord in the jack of the line on which the call was initiated. In the system described the telephone operator of a private secondary office is rung by plugging in the source of the ordinary ringing current from the connector which had been disconnected in making a transfer connection, in the same manner as for establishing a local connection, this current being disconnected from the lines as soon as the call has been answered.

   The transit or transfer transmitter selector is nevertheless fitted with devices enabling the operator of the transfer office to ring the operator of the private secondary office at any time if she so wishes.

  <Desc / Clms Page number 104>

 
This feature of the transfer transmitter selector will be described below.

   For this purpose it will be assumed that the transfer operator at the main transfer table has established a connection by means of the circuit of the DC cord on the line to which the conductors 501-502 belong through the selector switch. TS, of the TTS transfer transmitter selector and the RC rotary connector, on the line to which the conductors 881- 882 belong to the private sub-office X and it will also be assumed that the operator of this private sub-office has answered l '' call by inserting the answer plug of an unoccupied cord into the J8 jack,
Once the connection is established under these conditions, the status of the transfer transmitter selector T T S is as follows:

   The bell relay 601 is connected in bridge on the condenser 695 the relay 602 being energized on the circuit of which belong 1 immature 641 and the armature 649LE? distributor relay 603 of the battery current is energized on a circuit comprising the two large conversation conductors in series and the bridge on the line conductors of the telephone operator cord of the private sub-office whose plug is now inserted in the jackm J8. Relay 604 is energized from earth through frame 627 and its make contact.

   Relay 605 is energized on its top winding on the circuit from the ground to the trigger.

  <Desc / Clms Page number 105>

 555 which has been established through armature 633 and its make contact, by armature 628 and its work contact to relay 605. Relay 606 is actuated on the circuit comprising armature 631 and its contact contact. work, and the switch relay. 611 is energized on a circuit from the ground of the trigger conductor 555 by its prepre winding, the switch contact 633, the working springs 654 and by the winding of the relay 610 to the battery.

   The operator at the main transfer board can now ring the operator at the private secondary office again at any time by returning the Kt key to the ring position and thus supplying alternating current to the conductors of the line leaving the telephone line. main transfer table.



  Bell relay 601 of the TTS transfer transmitter selector draws its armatures in response to this alternating current and closes a circuit for the auxiliary bell relay 607, This circuit goes from ground to establish on the trigger lead 555, the contact armature 621 and this armature, the armature 630 and its work contact, by winding the relay 607 to the battery.

   Relay 607 is energized and closes the recall circuit which goes from earth through the make contact of armature 638 and this armature, the large lower conversation conductor, the bell relay of the telephone operator cord. from the private secondary office, the large upper conversation conductor, the 637 frame and its working contact,

  <Desc / Clms Page number 106>

   up to generator G6. The alternating current supplied by generator G6 makes the usual signaling devices of the telephone operator cord circuit of the private secondary office operate in known manner.

   The attraction of the armature 638 leaves the springs normally open, which this armature commands to close and thus establish a guard circuit for the relay 603 which goes from the earth through the resistor 616 to the springs that the armature 638 controls, l the lower right winding of the repeater coil R6 and the lower winding of the relay 603 to the battery. Relay 603 therefore remains energized for the duration of the recall, although its normal circuit has been opened by the separation of armatures 637 and 638 from their respective normally closed contact.



   The relay 601 releases its armature 621 and opens the circuit of the relay 607 as soon as the alternating current supplied to the conductors 501 and 502 is interrupted by the abandonment of the key k '; of the DC cord circuit of the transfer operator. Opening the circuit of relay 607 triggers the relay and restores the condi- tions of conversation of the circuits.



   In the description given above of the establishment of the different connections it has been assumed in each case that the selectors have each time encountered in their rotary search movement a free line in order to be able to push the connection to a next switch. In extremely busy traffic, however, it may happen that the lines

  <Desc / Clms Page number 107>

 accessible from a chosen floor of fixed contacts are all occupied at the particular moment when the selection operation takes place.

   In such a case the respective selector rotates its contact arms beyond the last set of fixed contacts up to the eleventh step of its rotation; in this position its rotary movement is naturally stopped automatically since the upright contact arm is not engaged on any contact. When the switch shaft is actuated in this position, so called cam springs are closed so as to establish a "not free" signaling circuit on the calling line.

   On hearing this "not free" signal, the calling subscriber is informed that the attempted connection is not in the process of being completed and that he must hang up his receiver and try again, If for example the primary switch selector SR (fig.l) had been pushed to its eleventh step of rotation because all the lines of a given stage were occupied, the cam springs 169 are closed and connect the conductor 191. connected to the generator for the signal "not free" shown in fig. 3 'to the lower conversation conductor via the working contact of the armature 143 and this armature, so as to transmit the "not free" signal to the subscriber who called.



  Cam springs 969 perform the same functions for the primary translator selector S R 'fig 9
The same can be said of the cam springs 219 and 219 'of the selectors S2 and S3 fig. 2. When selector S2 or selector S3 has turned its

  <Desc / Clms Page number 108>

 contact arm up to the eleventh step of its rotary movement the two-degree switch relay pulls its armatures in full since its lower winding is no longer short-circuited and since the line contact arms are now not engaged on contacts, the guard relay circuit, such as 128, of the translator selector is open, so that this relay trips and places the selector transferor in the conversation conditions.

   The connection of conductor 291 or 2911 with the lower talking conductor then results in transmitting the "not free" signal to the calling subscriber.



   If the receive LS selector were turned by turning to its eleventh position because the lines of the chosen step would have all been found occupied, the grounding of the lower terminal of the switch relay 411 would be removed, so that this relay would be free to operate. Since contact arms 451 and 453 are now not connected to ground and battery through the vertical magnet of a subsequent switch, as would have been the case if a line had been found. unoccupied, the guard relay 406 trips.

   The relay 406 being triggered and the relay 411 energized, a circuit is closed from the earth by the armature 423 and its normally closed contact, the working contact of the armature 432 and this armature 432 and the winding of relay 404 to the battery. The relay 404 attracts its armatures and, as explained above, disconnects the earth and the battery from the receiving conductors 401 and 402 by replacing them with the bridge comprising the winding of the relay 403 and resistance

  <Desc / Clms Page number 109>

 442 and 443.

   This operation triggers the triggering of the translator selector guard relay, such as the relay 128 of the translator selector S R, which results in putting the previous translator selector in the state desired for conversation. The rotary movement of the contact arms to their eleventh rotational step causes the closing of the cam springs 439 'and the connection of the conductor 491 connected to the generator of the "not free" signal to one of the conductors of arrival of the line. Since the conversation connection now extends from the calling station to the reception selector I S. the "not free" signal is transmitted to the calling subscriber to warn him of the lack of a free line. This subscriber is then supposed to hang up his receiver and try again a little later to establish a call.



   You have to proceed in a somewhat different way to notify the operator at the main transfer board when the transfer selector, or the transfer transmitter selector finds all the lines occupied on a chosen floor, since the headset The operator's earpiece is unplugged from the cord circuit when the operator transmits to. by means of his dial device a called number.

   For this reason the primary transfer selectors are fitted with additional sets of lady springs, which, when actuated, connect the earth of the intermittent current of the battery to the receiving conductors thus producing an intermittent flow of current in the conductors. line, in such a sense that it deter-

  <Desc / Clms Page number 110>

 intermittently undermines the excitement of the. relay polarized in the cord circuit and causes intermittent lighting of the control lamp.

     If, for example, the TS selector (fig. 5) turns its contact arms by its rotary movement to the eleventh rotation step, all the lines of the chosen stage being occupied, the cam springs 511 and 512 are closed and therefore connect the earth and intermittent battery current from switch I5 to line conductors 501 and 502, respectively. The resulting current flow through the polarized relay 502 of the circuit
CC of the cord is such that it causes the excitation of the relay 507 which will intermittently close the circuit of the lamp L. The flickering of the L lamp lets the transfer operator know that the primary transfer selector has found all busy lines.



   For the transfer transmitter selector, a different method is used to cause the transfer operator's cord circuit control lamp to come on intermittently. If the TTS transfer transmitter selector fig. 6 were to bring its contact arms by its rotary movement to the eleventh rotation step because all the lines of the stage chosen are occupied, the cam springs are closed, thus connecting the conductor 692 connected to the switch L5 (fig. 5) of the battery, to the lower conversation conductor, so that a circuit for the relay 603 comprising the upper winding to the right of the coil translator

  <Desc / Clms Page number 111>

 R6 is alternately open and closed.

   In addition, the rotation of the contact arms 661-664 leaving the fixed contacts, removes the earthing of the lower terminal of the winding of the switching relay 611 and thus allows the energization of this relay and since the contact arms 661 and 664 are now not connected with earth and battery respectively through the vertical magnet of the next switch, as they would ordinarily be if they had encountered a free line, the circuit of the guard relay 608 is open and operates its trip.



   The relay 608 thus closes a circuit going from the earth through the armature 641 and its rest contact, the working contact of the armature 649 and this armature itself (the relay 611 being now energized) and by winding relay 602 to the battery. Relay
602 by attracting its armatures inverts the connections of the receiving conductors to ground and to the battery, which reverses the flow of current in the polarized relay winding 507 of the DC circuit of the operator's cord and determines the excitation of this relay.



  Intermittent energizing and tripping of relay 603 intermittently closes and opens the circuit of relay 604. Relay 604 is energized and triggered in a corresponding manner and interrupts armature 628 from the battery connection with lead 556 intermittently allowing the springs controlled by armature 628 to intermittently open and close.



  These interruptions in the circuit of the polarized relay 507 will trigger its armature intermittently and will

  <Desc / Clms Page number 112>

 thus causing the L4 lamp to flicker, which indicates to the operator that all the lines have been found busy; it should then trigger the connection and try again.



   In the previous descriptions of the operations of the translator selector S R freeze 1, and of the selector selector S R 'fig. 9 the explanation of the utility of the various warning relays, such as relays 181 and 182 fig. 1 and relays 981 and 982 fig. 9 was postponed and their description will now be resumed. Starting again first at freeze 1, when it is first taken possession of the translator selector SR to establish a communication, the relay 128 attracts its armatures and closes a circuit to the armature 150. for lamp L and control relay 181 in series.

   The lamp L then lights up and the relay 181 attracts its armatures. A circuit is then established for the lamp L. which is closed to the armature 184 and the delayed ringing conductor 187 is earthed at 183. As explained, relay 128 remains energized until the last digit of the requested number has been transmitted by means of the dial device and it is then that a change of circuit at the connector takes place. cause the relay 128 to switch off. The circuit comprising the lamp L and the relay 181 in series is then interrupted and the relay 181 trips and interrupts the earthing of the delayed bell conductor 187, simultaneously opening the circuit of the lamp L ..

   Delayed ringing N 1 ($ ion shown

  <Desc / Clms Page number 113>

 in the drawing) is set so that it does not ring until after the bell conductor 187 has been held to ground longer than the time generally required to establish a connection. If, on the contrary, relay 128 is kept energized much longer than the interval for which the deferred ring N 1 has been set following a fault in the line, for example, it is because a calling subscriber having established part of a connection or simply picked up its receiver, neglected to hang it up, delayed ring N 1 is energized.

   This ringing tone attracts the attention of the telephone desk clerk.
2 that, which then determines by means of the lamp L 'the group of selectors, and, by means of the lamp L, the particular selector which is kept partially operated, the operator can then take the necessary measures. assignees to remedy the recognized drawback:
The delayed action ring N 2, controlled by the control relay 182 is mainly used to indicate when a subscriber connects to the line of another subscriber.

   If the subscriber of set A, for example, establishes a communication with another subscriber via the primary translator selector S B, the relay 129 is energized and thus locked on the trigger line when the called subscriber answers. The battery current distribution repeater relay 130 is also energized when a called subscriber answers. When the called party then hangs up his receiver, the relay 130 triggers and closes a circuit which goes from the earth through the armature 157 and its rest contact the armature 154 and

  <Desc / Clms Page number 114>

 its working contact, the lamp L'and by the winding of relay 182 to the battery.

   The relay 182 by attracting its armatures puts the common ring conductor 188 to the ground to the armature 185 and at the same time closes to the armature 186 a circuit for the lamp L3. If now the calling subscriber of set A does not also hang up his receiver after a reasonable period of time and therefore does not allow the switches operated to trigger in the manner described above, the delayed-action ring N 2 is switching on to attract the attention of the operator. of the office looking for the translator selector thus kept maneuvered, using the L3 lamp and the LI lamp which determines the respective selector, to take the measurements necessary and repair things.



   Returning then to FIG. 9, the control relays 981 and 982 have the same functions as those just explained, but their circuits are controlled in a somewhat different manner. For example when the translator selector SR 'is put into service, the relay 928 attracts its armatures and closes a circuit for the lamp L90 and the relay 981 in series, this circuit comprising the armature 955' and its rest contact, and the The armature 950 and its working contact Vais this circuit is opened each time the subscriber operates his dial call apparatus, since the relay 929 operates for the duration of the transmission of each series of pulses.

   Each time its circuit is opened, relay 981 trips and suspends the

  <Desc / Clms Page number 115>

 grounding of conductor 987 of the delayed-action bell. For this reason the delay for which the delayed-action bell N 1 is set does not need to be as long as in the previous case in this case, since there is no need to leave any time to establish a full connection.



  During the establishment of a connection, the relays 929 'and 932 of the translator selector SR' are energized. Once the connection is established and the called subscriber has answered the call, the repeater relay for distributing the battery current 930 is energized and causes: - 'tripping of relay 929 [' When the The called subscriber then hangs up his receiver after the end of the conversation, a circuit for the control relay 932 and the control lamp is completed from the earth by the contact, working armature 962 and this frame itself, the working contact of the armature 953 and this armature itself the armature 956 and its rest contact, by the lamp L91 and the winding of the relay 982 to the battery.

   The L91 lamp lights up and the relay 982 is energized putting the delay bell conductor 988 to earth and closing a circuit for the L93 lamp In this case also the alarm bell will be activated if the connection is not triggered after a reasonable period of time.

** ATTENTION ** end of DESC field can contain start of CLMS **.


    

Claims (1)

CLAIMS 1 The telephone system using automatic switches acting step by step and maneuvered <Desc / Clms Page number 116> by electrical pulses is characterized in that the motor magnet of a switch is supplied with current to perform its work by a circuit comprising in series two conductors leading from a previous switch. 2 In a telephone system according to claim 1 the magnet is traversed by current when the switch is turned on and is operated by intermittent shorting of a resistor in series with the magnet. 3 In a telephone system according to claim 1 for service between several different offices boosted current pulses are repeated by a limited-operation relay which, when energized, short-circuits a resistor in the outgoing circuit. 4 In a telephone system according to claim 1, a pulse circuit comprises two relays in serial lt one of these relays being of limited operation so as to respond only to pulses of increased current, while the other relay remains energized. during the entire duration of the pulse transmission. ABSTRACT EMI116.1 # m% "" # m * The telephone system using oommu- <Desc / Clms Page number 117> Automatic tators acting step by step and operated by electrical impulses is characterized in that the motor magnet of a switch is powered from the yard. rant to carry out its work by a circuit comprising in series two conductors leaving from a preceding switch