BE476206A - - Google Patents

Description

       

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    "Telephone system"
The present invention relates to telephone systems and particularly to systems comprising suburban offices and automatic switching means for establishing suburban calls.



   The object of the invention is to reduce the number of manual switching operations necessary to establish the suburban connections, to accelerate the establishment of these connections and to carry out the transmission of direction signals more efficiently and safely. and control to and by the automatic switching means employed in making the desired connections.

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   The invention is a telephone system comprising suburban offices, in which automatic switches are provided to direct incoming calls to called suburban and local offices, the conversation conductors of one or more. several trunk and selector circuits constituting a simplex circuit, whose balanced or unbalanced state is effective for controlling one or more differential signaling relays and whose resistance is effective for controlling one or more marginal signaling relays - According to a particular feature of the invention, a differential signaling relay, one winding of which is connected in series to a conductor of a simplex signaling circuit and the other winding of which is connected in series with the other conductor. of the simplex circuit, is, in service,

   sensitive to imbalance in the simplex circuit. Following another peculiarity, each of two polarized differential signaling relays has one winding in series with one conductor of a simplex circuit and another winding in series with the other conductor of the circuit simplex, one of said relays being operatively sensitive to an imbalance, which causes a higher current in one side of the simplex circuit and the other of said relays being operatively sensitive to an imbalance, which causes a higher current in the other. be next to the simplex circuit.



   Another feature of the invention relates to a suburban system, in which the conversation conductors of a suburban route selector comprise a simplex circuit for transmitting direction pulses from an incoming line associated with the. selector, to transmit direction or control signals to a next selector or to a relay.

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 Next telecommunications auxiliary gne used to establish a desired connection, to control the transmission efficiency of the associated incoming line and to control the tripping of the selector.



   Another feature of the invention relates to an arrangement, whereby the operator's dial, which is automatically disconnected from an output surburb auxiliary line after dialing the number on the dial, can be re-associated with the auxiliary line simply by pressing again a common dial key without disconnecting the circuit cord from the auxiliary output line and without reattaching it.



   Another feature of the invention relates to a suburban system, in which an incoming line can be connected to an auxiliary line of a plurality of auxiliary lines, by means of switching means comprising conversation conductors at. a signaling conductor, the circuits being closed by the signaling conductor in order to control the artificial complement or complementary transmission lines associated with the incoming line, while the connection between the main line and a desired auxiliary line is established, and to transmit control signals from the auxiliary line connected to the incoming line.

   According to this peculiarity, the winding of a marginal relay is connected in circuit with the winding of a normally actuated relay and with the signaling conductor, the normally actuated relay being maintained in action while the connection of the relay. the incoming line to an auxiliary line is established, the marginal relay being actuated when connecting the line in-

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 trante to the auxiliary line, so as to move the control of the additional transmission from the circuit, through the signaling conductor, to a circuit comprising the conversation conductors in parallel, the answer to the call by an operator or a subscriber having the effect of opening the complement control circuit on the signaling conductor,

   so as to trigger the normally actuated relay and thus connect the signaling conductor to a response control relay associated with the incoming line.



   The invention will emerge more clearly from the description of the telephone system according to the invention illustrated in the accompanying drawings. The invention is obviously not limited in its application to the particular system shown in the drawings.



   In these drawings: FIG. 1 represents an operator cord C1 and a position circuit PC1; FIG. 2 shows a dial circuit DC1 associated with the position circuit PC1 of FIG. 1; Figure 3 shows output jacks J1 and J2, response jacks J3 and J4, and an auxiliary output line circuit CT1 associated with jack J1; FIG. 4 shows a two-way auxiliary line circuit TWT1 and a composite signaling circuit CS1 connected to one end of a suburban line T1 and to the auxiliary output line circuit OT1 of FIG. 3;

   figure 5 shows a suburban route selector TS1 associated with the two-way auxiliary line circuit TWT1 of figure 4, an auxiliary suburban route selector AS1 and an incoming auxiliary line circuit IT1 associated with the answer jack J3

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 in Fig. 3, Fig. 5 also showing another two-way auxiliary line circuit TWT4, an auxiliary line output circuit OT4 and a composite signaling circuit 4, all associated with a suburban auxiliary line T4; Fig. 6 shows the composite signaling circuit CS2 and the two-way auxiliary line circuit TWT2, connected to the other end of the suburban line T1;

   Fig. 7 shows a suburban route selector TS2 and an auxiliary line output circuit OT2, both associated with the two-way auxiliary line circuit TWT2 of Fig. 6, Fig. 7 also showing another suburban road selector TS3; Figure 8 shows an operator lead C2 and a PC2 position circuit, output jacks J5 and J6, response jacks J7 and J8, an auxiliary suburban route selector AS2, and an incoming circuit. auxiliary line IT2, connected to jack J7, figure 8 also showing an auxiliary suburban line T3, a composite signaling circuit CS3 and a two-way auxiliary line circuit TWT3 connecting the auxiliary line T3 to the selector TS3 of figure 7 and an auxiliary line output circuit CT3 connecting this auxiliary line to the jack J6;

   Figure 9 shows a voice frequency signaling circuit SC5 and a two-way auxiliary line circuit 19 TWT5 connected to a suburban auxiliary line T5, the far end of which is also arranged to transmit signals to voice frequency, and Figure 10 shows the relationship between each of Figures 1 to 8 inclusive to form an agency.

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 clean to operate.



   The system shown in the drawings includes a plurality of suburban offices, each of which includes a suburban board with operator positions and cords for answering calls from manual or automatic local offices, suburban subscriber lines, telephone calls, and telephone numbers. rural automatic offices or other suburban offices and for connecting an incoming call to an auxiliary switching line leading to a called manual or automatic local office, called suburban subscriber line, rural automatic office or auxiliary line Suburban. Output jacks, such as Jl, J2 in an office, and J5, J6 in a second office, establish the connection to auxiliary switching lines, to suburban lines,

   to auxiliary lines leading to rural automatic offices and to suburban auxiliary lines. Answer jacks like J3, J4 in one office and J7, J8 in the second office, are connected directly to auxiliary lines registration, suburban subscriber lines, auxiliary lines from rural automatic offices, and suburban auxiliary lines. The terminals of the arrival selector banks or suburban route auxiliaries, such as TS1,
TS2, TS3, TS4, AS1 and AS2, are also connected to the various auxiliary lines and lines other than the auxiliary recording lines.



   Operator positions PC1 and PC2 are provided with dials and dial circuits to control the operation of arrival selectors and suburban route auxiliaries in other suburban offices and to control the operation of the suburban.

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 usual suburban train in local or rural dial offices. The call circuit DC1 and the auxiliary line circuit OT1 are arranged, as described above, so that the dial can be reconnected to the pulse receiving relay of the auxiliary line circuit, by actuating the dial key again. position without first disconnecting the cord from the auxiliary line circuit.



   The suburban auxiliary line T1 is a two-way auxiliary line between a first and a second office, and is packaged to transmit composite signals. At one end, the auxiliary line T1 is connected to the composite signal transmission circuit CS1, to the two-way auxiliary line circuit TWT1, to the output circuit of the auxiliary line OT1 and to the suburban road arrival selector. TS1. At its other end, the auxiliary line T1 is connected to the composite signal transmission circuit CS2, to the two-way auxiliary line circuit TWT2, to the auxiliary output line circuit OT2 and to the arrival selector of. suburban road TS2.

   The two-way auxiliary line circuits TWT1 and TWT2 also connect to terminals in the auxiliary suburban route selector bank AS1 and AS2, so that the auxiliary line T1 can be grasped either by connecting a cord.
Cl or C2 or output jack Jl or J5, or by activating an input suburban route selector and an auxiliary suburban route selector.



   Composite signaling circuits CS1 and CS2, two-way auxiliary line circuits
TWTL and TWT2, the output auxiliary line circuit OT1, the input suburban route selector TS2 and the

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 Auxiliary input line circuit IT2 are shown in detail. The auxiliary output line circuit OT2, which is only partially shown, is similar to the auxiliary output line circuit OT1; the input suburban route selector TS1 is similar to the input suburban route selector TS2, and the auxiliary line circuit IT1 is similar to the auxiliary input line circuit IT2. The auxiliary suburban route selectors AS1 and AS2 are similar to the suburban route selector TS2.



   The suburban auxiliary line T4 is part of a group between the first office and a third office which is not shown in the drawings. The suburban auxiliary line T3 is part of a group between the second office and a fourth office, not shown in the drawings. The associated compmsite signaling circuits CS3 and CS4, two-way auxiliary line circuits TWT3 and TWT4, output auxiliary line circuits OT3 and OT4, and input suburban route selectors TS3 and TS4 are similar to the corresponding circuits and the selectors associated with the suburban Tl suburban lines.



   The suburban auxiliary line T5, which is arranged to transmit voice frequency signals instead of composite signals, is part of a group between the second office and a fifth office, not shown. The associated two-way auxiliary line circuit TWT5 is a variation of the two-way auxiliary line circuit TWT2 of Fig. 6, to work with the voice frequency signal transmission circuit SC5. The output auxiliary line circuit and associated input suburban route selector is similar to the auxiliary line circuit

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 exit OT2 and the entry suburban route selector TS2.

   A proper arrangement to operate is formed by placing Figure 9 on the left side of Figure 7 and Figure 8 on the right side of Figure 7. The reference notations applied to the relays of the auxiliary line circuit TWT5, which correspond to the relays of the auxiliary line circuit TWT2 of figure 6, are the same with regard to the digits of units and tens.



   The suburban route selectors TS1, TS2, TS3 and TS4 and the auxiliary route selectors AS1 and AS2 are of the well known type with two stepping directions. The switches TS1, TS3, TS4, AS1 and AS2 are each represented by a series of brushes and one or more series of terminals, but none of the magnets of the relays or other devices associated with these switches are shown. The TS1 suburban road selector bank is represented by a single series of terminals, but this selector also includes all the magnets, relays and other associated devices.



   Assume now that a call arriving at the suburban switchboard in the first office is answered by connecting the RP plug of cord C1 to an answering jack, such as J3 or J4. The conversation key TK having been actuated, and the position circuit being unoccupied, relay 10 is actuated by the excitation of its left winding. Relay 10 closes a circuit to actuate relay 20 of the position circuit, and relay 20 closes the blocking circuit, through the right winding of relay 10.



  The operator's telephone apparatus is connected, via the contacts of relay 10, to the calling line or auxiliary line. To extend

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 On connection, the FP plug is connected to an output jack, such as J1 or J2, and, if the connected auxiliary output line is arranged to respond to the dial, as is the case. if the call setup includes selective operation of one or more suburban route selectors or selective operation of a suburban train in a local or rural automatic office, the DK dial key is brought to its front position.

   Although the cord and the position circuits C1 and PC1 are arranged so that the dial D1 can be connected to each end of the cord, only the relays and connections necessary to transmit the call through the FP plug, are represented . It is further assumed that, during the call in question, the FP plug is connected, via the jack J1, to the auxiliary output line circuit OT1. A circuit is closed by the conductor body of the FP plug and the contacts of the TK key to actuate relays 21 and 22 of the position circuit and relay 54 of the auxiliary output line circuit. The relay 21 closes a circuit to actuate the relay 23 and the relay 22 closes a circuit lighting the monitoring lamp F1 of the cord.

   When the DK dial key is actuated and relay 23 operates, dial circuit relay 24 DC1 operates, disconnecting the end and periphery conductors of the FP plug of the telephone set from the telephone. operator and closing a circuit to actuate relay 25. Relay 25 closes a circuit to turn on the pilot light of the DP dial and a circuit, which includes the rear contacts of relays 28, 35, 36 and 31, to actuate relay 26 Relay 26 closes a circuit to actuate relay 27. Relay 27 closes a circuit to actuate relay 28. Relay 28

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 blocks under control of relays 25, 35, 36 and
31 and opens the operating circuit of relay 26.



   In the auxiliary output line circuit OT1, operation of relay 54 closes a circuit to operate relay 68. Relay 68 locks under control of relay 69 and closes a circuit to operate relay 58. Relay 58 closes a circuit. circuit which turns on the occupancy lamps, such as BL associated with jack 1 and other jacks connected in combination with jack 1, closes circuits to actuate relays 64 and 69, closes a circuit including the inner lower contact of relay 78 to operatively energize the upper winding of relay 70, closes a circuit to actuate relay 76, connects the ground to the conductor body 93 of the two-way auxiliary line circuit TWT1, disconnects the winding from relay 56 of the conductor body 93,

   Connects the winding of the monitoring relay 55 to the front contact of the signaling relay 90 of the composite signaling circuit OS1, and disconnects the front contact of the signaling relay 90 from the conductor 95 leading to the windings of the relays 100 and 101 of the auxiliary line circuit two-way TWT1. The operation of relay 64 closes the circuits to actuate relays 60 and 61, connects the ground to the conductive body 93 and connects the ground, through its front central and lower contact, to the posterior contacts of relays 79 and 66. , and conductor @ 52 to the peripheral conductors of the Jl jack and the FP plug. The ground connected to the driver, 93 prevents the selection of the auxiliary line T by a suburban route selector, such as AS1, and actuates the relay 115.



  Relay 115 is blocked and disconnects the windings
AT

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 of the relays 100 and 101 of the driver 95. The operation of the relay 69 opens the blocking circuit of the relay 68, but the relay 68 remains under the control of the relay 54. The slow release relay 68 and the relay are actuated slow 69 / has the effect of preventing tripping of relay 70, if it is actuated, before the FP plug is fully placed in jack J1.



  Operation of relay 76 maintains the operative excitation of the upper winding of relay 70 independent of relay 78. The armatures of signaling relays 90 and 190 are normally held in the position shown in the drawings by the excitation. of the upper bias windings of these relays.

   The operation of relay 70 closes a circuit from battery B1, passing through resistor 75, the front contact of relay 70, delay coil 89, the central winding of relay 90, the upper windings of the coils. delay 86, the upper conductor of the auxiliary line T1, the upper windings of the delay coils 186, the central winding of the relay 190, the delay coil 189, the rear contact of the relay 170, and the contacts of relays 210 to 211 and terminating at earth Closing this circuit activates relay 190 and constitutes the outlet of the auxiliary line Tl, so as to protect the auxiliary line when it is busy, as will be described. below.



  Any variation in the excitation of the central windings of relays 90 and 190, unlike the earth potential between the auxiliary line T1 terminating the offices, is compensated for by the excitation of the lower polarization windings of these relays in an earth to earth circuit passing through the lower conductor of the auxiliary line Tl. Lefonc-

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 Operation of relay 60 closes the contacts intended to keep the occupancy lamps BLlit. Relay
60 also closes a network including resistors
72, 73 and 74, the voltage regulating lamp 71 and the central bias winding of the relay 70.

   The voltage regulator lamp has a high temperature-resistance coefficient and variations in its resistance, due to variations in the voltage of the signal battery B1, affect the excitation of the central winding of the relay 70, so as to compensate for changes in the voltage of the signaling battery. The relay 61 closes a circuit starting from the battery, and passing through the resistor 67 and the rear contact of the relay 66, so as to maintain the complementary control relay 83 normally actuated. The normally closed circuit, intended to actuate the relay 83, comprises the lower rear contact of the relay 61, the resistor 62: and the posterior contacts of the relays 117 and 107 of the auxiliary two-way line circuit TWT1.



   When the slow tripping relay circuit
26 is opened by actuation of relay 28, as described above, relay 26 remains actuated for an interval long enough for relay 69 of the auxiliary line circuit to be actuated. At this moment, a circuit closes having the effect of maintaining the relay 27 activated and activating the relays 29 and 78.



   This circuit starts from the battery, passes through the winding of relay 27, the winding of relay 29, the upper front contact of relay 27, the upper rear contact of relay 32, the upper front contact of relay 24, the front contact inside left of relay 10, the contacts of the RK call key, the con-

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 FP plug and jack Jl tip conductors, conductor 51, the rear contact of relay 66, the winding of relay 78 and leads to earth at a front contact of relay 69. Relay operation 29 closes a circuit to activate relay 31.



   Relay 31 closes a circuit to actuate the relay
32, and closes a circuit from the battery, passing through resistor 34, the upper front contact of relay 31, the pulse contacts of dial D1, the winding of relay 35, the rear contact of relay 26, the front contacts of relays 24 and 10, the peripheral conductors of the FP plug and the jack Jl, the conductor 52, the rear contacts of the relays
66 and 79 and resistor 65, and terminating in earth at an earlier contact of relay 64.

   Relay 32 opens the circuit passing through the windings of relays 27 and
29 and connects the tip conductor of the FP plug, through resistor 33, to the battery, to keep relay 78 actuated. Although relays 27 and 29 trip, relay 31 is kept actuated. by relay 32 and relay 32 is kept actuated under the control of the dial key. Relay
31 keeps relays 20 and 24 activated. Operation of relay 78 closes a circuit for actuating relay 79 and opens the circuit, by the winding of relay 76. Relay 79 locks under control of relay 69 and connects the actuating winding of relay to pulse 70 in series with conductor 52 and pulse contacts of dial Dl.

   As the operation of relay 78 disconnects the battery, at its lower and inner rear contact, from the actuating winding of relay 70 and the release of the relay
76 disconnects the batteire, at its previous contact, from this winding of relay 70, relay 70 is now

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 ready to respond to the impulses created by the operation of the dial Dl. The lower bias winding of relay 70 is connected in series to a battery of the same voltage as the dial battery, so as to compensate for variations in the voltage of this battery.



   The desired suburban route number is dialed, along with the local office code and the called subscriber number, if the called subscriber's line is in an automatic office. Pulse relay 70 repeats the dial pulses, via auxiliary line T1, to relay 190 of composite signaling circuit CS2. Each time the dial is moved from its normal position, relay 37 operates, so as to keep relays 32 and 31 actuated, independent of the dial key. When the manipulation of the dial is completed, the key DK is returned to the normal position and the relay 37 trips.

   The relays 32, 31, 2 and 25 'then trigger one after the other and the FP plug is thus reconnected to the operator's telephone apparatus. While the conversation key TK is actuated, control signals are received, through the annular conductor of the FP plug, by the marginal relay 22, and the relay 22 controls the monitoring lamp FL. When the TK 'conversion key is returned to the normal position, relays 10,
21, 20, / 22 and 23 are triggered and the lamp FL is controlled, through the conductive body of the plug FP, by the control relay 55 of the auxiliary line circuit OT1.

   Triggering of relay 32 opens the circuit passing through resistor 33 and the tip conductor of the FP plug, so as to trigger relay 78 and thus reconnect the battery by

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 the lower contact of the relay 78, so as to keep the relay 70 activated before the triggering of the relay 31 opens the circuit of the dial, the relay 31 being slow to trigger The triggering of the relay 78 closes circuits comprising a contact of relay 79, to actuate relay 66 and reactivate relay 76. Relay 66 disconnects conductors 51 and 52 from the winding of relay 78 and from the contacts of relay 79, opens the circuit passing through resistor 67 and the relay 83, and connects the conductors 51 and 52, by the windings of the delay coil 80,

   and the front contacts of relay 61, by the windings of relays 63 and 77 in parallel, and by the winding of the complement control relay 83 to earth. The complement control relay 83 is then kept actuated. in series with the resistors 11 and 12 .du position circuit PC1, as long as the conversation key of the cord C1 is activated.



  When the conversation key has been returned to its normal position and the relay 10 trips, the complement control relay 83 is controlled by the tip and periphery (annular) conductors of the auxiliary call line or line, to which the RP plug is connected. If, under these conditions, the relay 83 trips, the relay 84 operates to short-circuit the artificial complements or complementary transmission lines P1 and P2. Relay 66 also interrupts the normally connected voice frequency repeater termination, comprising a resistor, capacitor, and a back contact of relay 56.



   The aforementioned operation of relay 190, when the output auxiliary line circuit CT1 is taken, closes a circuit starting from earth and terminating,

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 via the previous contact of the relay
190, of the rear contacts of relays 158 and 160 of the auxiliary output line circuit OT2, of the conductor
195, from the rear contact of relay 215, from the two-way auxiliary line circuit TWT2, from the rear contact of relay 202, to the winding of relay 200 ..



   The relay 200 operates, disconnecting the relay 215 from the conductor 193, connecting the earth to the conductor 193, so as to protect the auxiliary line T1 against any selection by a suburban route selector, such AS2, and actuating the relay 156 of the line circuit. OT2 output auxiliary. The relay 156 connects the battery to the socket of the output jacks J5, so as to make these jacks occupied for the test and closes a circuit to actuate the relay 160. This relay 160 closes a circuit to turn on the occupancy lamps BL5 . Although relay 160 opens the connection, normally closed, between the front contact of relay 190 and conductor 195, relay 156 maintains a connection between the front contact of relay 190 and the conductor.
195, so as to keep the relay 200 actuated.

   The relay 200 also closes a circuit to actuate the relay 201 of the two-way auxiliary line circuit TWT2 and the relay 225 of the suburban road selector TS2. This circuit includes the earth at the front contact of relay 190, the rear contact of relay
158, the previous contact of relay 156, the driver
195, the rear contact of relay 215, the winding of relay 201, the rear contact of relay
216, the winding of the marginal relay 206, the front contact of the relay 200, then, in simplex, the two windings of the differential relay 205, the rear contacts of the relay - 161, the windings of the delay coil 180 , the conductors 181 and 182, the previous cotact of the relay 200, the conductors

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 tor 221 and 222, the rear contacts of relay 229 of selector TS2,

   resistors 231 and 232, resistor 230, a rear contact of relay 229 and the winding of relay 225. Relay 206 does not work, because it is marginal, and relay 205 does not work, because its windings are differentially excited. The operation of the relay 201 causes the operation of the slow tripping relay 202. When relay 202 is operating, relay 200 is maintained actuated by resistor 204 grounded to the front contacts of relays 201 and 202. The relay
202 connects the earth of the rear contact of the relay
217 to the conductive body 223 of the selector TS2, so as to control the triggering of this selector, as will be described below.

   Relay 219 is normally actuated in series with the upper coil of the relay
207 and in series with resistor 203 in parallel with resistor 220 between selector TS2. The connection of the coil of relay 219 and resistor 220 includes a front contact of relay 219, conductor 224, the "11th step" spring contacts, and a rear contact of relay 229. The re lais 207 is marginal and is normally not actuated.



  When relay 202 operates, relay 219 is held actuated in series with resistor 220, until relay 229 operates, as will be described below. Operation of relay 225 closes a circuit to actuate slow-trip relay 226.



   The relay 226 connects the earth to the conductive body 223 and also connects the earth, through its front lower and outer contact, to a warning circuit, so that a warning device will be activated in the event that the relay 225 fails. . receives no pulses within a predetermined time interval.

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   When the calling operator dials the first digit of the suburban road number on the dial, the pulses are repeated, by relay 70 of the auxiliary line circuit OT1 on the tip conductor of the auxiliary line T1, to relay 190 of the composite signaling device CS2. The tripping and re-actuation of relay 190, in response to each impulse, causes a corresponding tripping and reactivation of relays 201 and 225. Being slow to trip, relays 202 and 226 remain on. action during the response of relays 201 and 22 $ to the impulses of the dial.



  Tripping of relay 225 in response to the first pulse closes a circuit to actuate vertical feed magnet 233 and slow trip relay 227. Each operation of magnet 233 raises the brushes one step. The VON vertical shunt springs are actuated, as soon as the switch shaft moves out of its normal position, by closing a circuit, which includes the front contact of relay 227, to actuate relay 228. When relay 225 remains actuated after having received the last pulse of the series generated by dialing the first digit of the suburban road number, relay 227 trips, opening the circuit for relay 228 and closing a circuit to operate the rotary feed magnet 234.

   Relay 228 is kept actuated by its upper front contact, until magnet 234 operates. Operation of magnet 234 engages the brushes with the first set of terminals at the selected level in response to the dial pulses. Tripping of relay 228 causes magnet 234 to trip. If this series of terminals is occupied, test brush 237 encounters an earth potential, which has the effect of causing relay 228 to reactivate. relay winding

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 228 being connected, by means of contacts of the VON springs, of the posterior contact of the magnet 234 and of a posterior contact of the relay 229 to the brush 237.



  The reactivation of the relay 228 causes the reactivation of the magnet 234, so as to bring the brushes to the closest series of terminals. The operation of the magnet 234 causes the triggering of the relay 228, and the triggering of relay 228 triggers the triggering of magnet 234.

   This cycle of operations is separated to advance the brushes stepwise until test brush 237 encounters a terminal which is not marked by a ground potential connected thereto. the relay 229 is actuated by the current flowing in a circuit comprising the battery, the winding of the relay 228, the contacts of the VON springs, the posterior contact of the magnet 234, the winding of the relay 229, the contact of normally closed of the 11th pitch / rotation springs and earth on the conductor body 223. Being marginal, the relay 228 does not operate in series with the relay 229. The relay 229 disconnects the relay 225 from the conductors 221 and 222 and connects these. conductors, by brushes 235 and 236, to the line relay (not shown) of the auxiliary suburban route selector AS2.

   The earth potential connected, through the rear contact of relay 216 and the upper front contact of relay 202 to the conductive body 223 is brought, through a front contact of relay 229, to test brush 237, to indicate that the selected suburban route auxiliary selector is occupied and to prevent this selector from being entered by any other suburban route selector that has access to it.

   Relay 225 trips by causing relay 226 to trip, and relay 226 disconnects ground from the warning circuit. The operation of the relay

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 229 disconnects resistor 220 from conductor 224 and connects conductor 224, through brush 238, to the selector circuit AS2, in which there is a connection, through a resistor similar to resistor 220, to keep relay 219 energized.



   Assume that the desired suburban road number is': a number of two. figures. In this case, there are no intermediate selectors between selector TS2 and selector AS2. If you need a large number of suburban routes, you will need one or more additional selectors in the train to choose a desired suburban route, and, if one selector is sufficient, the TS2 selector will have direct access to the suburban routes. groups of auxiliary lines which, in the system shown, are connected to the banks of the AS2 auxiliary selectors.

   After dialing the second digit of the suburban road number, the auxiliary selector AS2 of the suburban road is operated directly, so as to choose a desired group of auxiliary lines and activated automatically / so as to enter a free auxiliary line in the chosen group. The AS2 selector can have access to auxiliary lines, to local offices, either manual or automatic, to suburban lines which extend to suburban subscriber offices or to other suburban offices, to trunk circuits. input auxiliaries, such as IT2, which terminate at places of a suburban switchboard, and groups of automatic suburban auxiliary lines, one of these groups being represented by the auxiliary line Tl and another by the auxiliary line T3.



   It is assumed that the suburban road number entered on the dial has the effect of activating the TS2 and AS2 selectors to choose the line circuit.

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 auxiliary input IT2, terminating in a J7 jack, at an operator location comprising a C2 lead and a PC2 position circuit.

   The relay 201 of the two-way auxiliary line circuit TWT2 is kept active and the relay 251 of the auxiliary input line circuit IT2 is actuated by the current, in a circuit starting from the earth, passing through the earth. front contact of relay 190, rear contact of relay 158, front contact of relay 156, conductor 195, rear contact of relay 215, winding of relay 201, rear contact of relay 216, winding of relay 206, the front contact of relay 200, then in simplex, by the two windings of relay 205, the rear contacts of relay 161, the two windings of the delay coil 180, conductors 181 and 182, the front contacts of the relay 200, conductors 221 and 222, front contacts of relay 229, brushes 235 and 236, selector AS2,

   the conductors 241 and 242, the two windings of the delay coil 245, the resistors 246, 248 and 249 and leading to the winding of the relay 251. The resistors 246, 248 and 249 are chosen so that the current flowing on one side of the simplex is sufficiently stronger than the current flowing to the other side of the simplex, to cause the operation of the differential relay 205. But the relay 205 is tripped almost immediately, because the simplex is balanced, as soon as normally actuated relay 271 trips as a result of the operation of relay 256, as described above. The current in the simplex circuit is not strong enough to actuate marginal relay 206.

   Relay 251 closes a circuit to turn on the response lamp AL1, connected

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 This draws ringing or calling current 250 through capacitor 275 to conversation conductor 262, thereby transmitting a call signal to the calling operator to indicate that an operator is busy sending.



  While the simplex circuit is closed to actuate relay 251, a circuit is closed to actuate relay 219, to actuate marginal relay 207 of the two-way auxiliary line circuit TWT2, and to actuate relay 256 of the IT2 input auxiliary line circuit, this circuit including earth, the top winding of the relay.



  207, the winding and the front contact of relay 219, the conductor 224, the rear contact of the "11th step of rotation" springs of the selector TS2, the front contact of the relay 229, the brush 238, the selector AS2, the conductor 244, the rear contact of relay 274 and the lower winding of relay 256.



  Relay 207 is blocked by its lower winding and a front contact of relay 202. Relay 256 is blocked by its upper winding at holding earth potential connected to conductor 243 from the rear contact of relay 216 of the auxiliary line circuit to two directions TWT2. Normally, relay 271 is kept actuated in a circuit comprising resistors 266,267, 268 and 269 and the coil of relay 270 and including the back contact of relay 256. Although relay 271 is indicated as a polarized relay, it may be a non-polarized and sensitive relay.

   When relay 256 operates, relay 271 trips, opening the circuit around resistor 247 and closing a circuit around resistor 248, so as to

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 to balance the simplex circuit and to cause the trip of the relay 205. When the relay 205 is tripped and the relay 207 activated, the relay 183 trips and the relay 184 activates the short-circuiting complements P1 and P2.



   When a plug of a C2 cord is inserted into the J7 jack to answer the incoming call, the relay 272 is actuated, since the battery is connected to the body of the plug, the C2 cord and the PC2 position circuit being similar to the lead C1 and to the position circuit PC1 shown in figure 1. The relay 272 closes a circuit to actuate the relay 273. Relay 273 closes a circuit, which includes a front contact of relay 251, to actuate relay 274. Relay 273 also disconnects the repeater termination, including capacitor 276 and resistor 277, from conductors 261 and 262. This termination, normally connected to the terminals of these conductors, prevents the voice repeater of a connected suburban auxiliary line from whistling before answering an operator call.

   Relay 274 'locks to earth connected to conductor 243, opens the bell signal connection, turns off lamp AL7, disconnects monitoring conductor 244' from the operating winding of relay 256, and connects This conductor in series with a positive current from relay 270 to earth to a previous contact of relay 273, thus causing the relay 219 of the two-way auxiliary line circuit TWT2 to trip. Triggering of relay 219 disconnects its winding from conductor 224 and connects this conductor, via the rear and upper contact of relay 215, to the winding of response monitoring relay 211.

   Relay 211 thus operates in

 <Desc / Clms Page number 25>

 connecting the battery, by means of the resistor 175, the front contact of the relay 211, the rear contacts of the relays 210 and 170 and the coil
189 does not delay / to the windings of the relay 190, thus causing / the operation of the relay 90 at the other end of the auxiliary line T1. The relay 90 closes a circuit to actuate the control relay 55. The relay 55 opens the circuit passing through the lower, low resistance winding of relay 54. Since the upper winding of relay 54 is a high resistance winding, current in the circuit passing through the conductive body of the FP plug and the FL lamp is reduced so as to extinguish the FL lamp to indicate to the calling operator that the call has been answered.



   The complement control relay 271 is kept actuated in a simplex circuit passing through conductors 261 and 262 and terminating at the battery in the position circuit of the operator PC2, as long as the conversation key of the C2 cord is actuated. When the connection is extended, through the other end of the C2 cord, to an auxiliary line or line and the C2 cord conversation key is returned to the normal position, the relay
271 is controlled by the auxiliary line or line, to which the other end of the C2 cord is connected.



   If relay 271 trips, it unbalances the simplex circuit to cause the relays to reactivate.
205 and 183 and the triggering of relay 184, while opening the short-circuit around the complements P3 and P4. If relay 271 is kept energized, the simplex is balanced, relays 205 and 183 are not energized, and relay 184 short-circuits complements P3 and P4.

 <Desc / Clms Page number 26>

 



   The calling operator can call back the answering operator by moving the bell or call key to the lower position, so as to connect the signaling battery to the tip conductor of the FP plug, the battery having a sufficiently high voltage, for example 45 to 50 volts, to operatively energize the winding of relay 63.

   The relay 63 closes a circuit to actuate the relay 59 and a circuit to keep the relay 70 actuated. When the bell or call key is returned to the normal position, the relay 63 trips. After the release of the relay 63 and before the tripping of relay 59 with slow tripping, the upper signaling condiictor of the auxiliary line / relay 70 dc enc by temporarily transferring Tl from the battery to earth, so as to trigger the tripping and re-activation of relay 190. The tripping and reactivation of relay 190 cause tripping and re-activation of relays 201 and 251. Being slow tripping, relay 202 remains actuated. Triggering of relay 251 causes relay 252 to operate.

   Relay 252 connects the low resistance winding of relay 254 in parallel with the high resistance winding of relay 272, causing the cord monitor lamp (not shown) to light up. Relay 254 operates and locks out ..When relay 251 operates again, relay 252 trips and switch I is connected to the winding of relay 257.



  Relay 257 is alternately actuated and tripped 120 times per second under the control of switch I. Each time relay 257 operates, it closes a holding circuit for relay 254 and disconnects the low resistance winding of relay 254 from the body. conductor 263, so that the monitoring lamp of the cord is extinguished. The cord lamp is

 <Desc / Clms Page number 27>

 so on to signal the operator to respond to the callback until the lanyard talk key is pressed. When the conversation key is activated, the marginal relay 254 trips, but the relay
272 remains actuated. The triggering of relay 254 disconnects the winding of relay 257 from switch I.



   If the answering operator wishes to transmit signals to the calling operator, operation of the bell or call key connects to the driver 261 a battery of a voltage high enough to actuate the marginal relay 270. While the control key buzzer and relay 270 are actuated, earth is disconnected from conductor 244 by triggering relay 211. Triggering of relay 211 causes successive triggering of relays 90 and 55 at the calling end of auxiliary line T1. The relay 55 reconnects the low resistance lower winding of the relay 54 in parallel with the high resistance upper winding, so as to light the FL lamp of the C1 cord to remind the operator.



   If the answering operator disconnects the C2 cord from the circuit of the auxiliary line IT2, while the calling cord C1 remains connected with the output circuit of the auxiliary line OT1, the relays 272 and 273 trip. Relay 273 reconnects the capacitor
276 and resistor 277 through conductors 261 and 262, disconnects ground from conductor 244 to trigger relay 211 and thereby correspond with the calling operator as described in the previous paragraph, and close a circuit to operate the re - leave 255.

   Relay 255 connects the battery to the two windings of the delay coil 245, with current flowing through the winding of the marginal-206 relay.

 <Desc / Clms Page number 28>

 of the two-way auxiliary line circuit TWT2 being increased enough to cause it to operate. Relay 206 closes a circuit to actuate relay 216, and relay 216 locks up under control of relay 202. Operation of relay 216 disconnects the earth of conductor 223, thereby triggering relay 229 of selector TS2, tripping of the corresponding relay in selector AS2, and tripping of relays 256 and 274 of the auxiliary input line circuit IT2.

   Triggering of relay 229 closes a circuit to actuate trigger magnet 239, and the shaft and brushes are then returned to the normal position. Opening the upper contacts of the VON springs, when the shaft is in its normal position, triggers the magnet 239. The shaft and the brushes of selector AS2 are returned to the normal position in the same way. The above mentioned operation of relay 216 causes relays 201, 205 and 206 to trip, but keeps relay 200 energized. Relay 216 also closes a circuit to hold relay 211.



  The triggering of the relay 201 triggers the triggering of the relay 202, and the relay 202 triggers the relays 216 and 211. The triggering of the relay 211 causes the lighting of the lamp FL of the cord C1 and the triggering of the relay. 216 closes the circuit, described above, to actuate relays 201 and 205 and relay 225 of selector TS2. Relay 201, in turn, closes the circuit to actuate relay 202, and relay 202 reconnects earth from the rear contact of relay 216 to conductor 223. The calling operator can now reconnect the dial of cord C1 and feedback ner the selector TS2 and the following switches, to establish another. call, without the auxiliary line Tl having been released between calls.

   By reactivating

 <Desc / Clms Page number 29>

 the conversation key TK, relays 10, 20, 21, 22 and 23 are reactivated, and by reactivating the dial key DK, relays 24, 25, 26, 27 and 28 are reactivated. The operation of relay 28 triggers relay 26, relay 27 is maintained and relay 29 operates via the tip conductor of the FP plug in series with the windings of relays 63 and 83. Relay 63 is marginal and does not work in this circuit, since the battery voltage connected to the relay winding 27 is only a 24 volt battery.

   The operation of relay 29 causes the successive operation of relays 31 and 32 and the tripping of relay 27, thereby reconnecting the battery, through resistor 34, to the annular or peripheral conductor of the relay. the FP plug, then via the conductor 52, the front contact of the relay 66; of the lower coil of the delay coil 80, of the front contact of the relay 61, of the lower coil of the relay 77 and of the coil of the relay 83, on the ground. Relay 77 operates and is blocked by its upper winding under the control of relays 79 and 78. Operation of relay 77 triggers relay 66.

   Relay 66 in turn closes the circuit starting from the battery, and passing through resistor 33 and the tip conductor of the FP plug, to actuate relay 78. When relay 78 is actuated, it - upper bearing of relay 70 is under the operative control of the pulse contacts of dial Dl, and the dialing of another suburban road number results in the resetting of the selector TS2 et.d ' an auxiliary selector AS2, as described above.



   When the calling operator disconnects the C1 cord from the auxiliary line OT1, the relay 54 trips.

 <Desc / Clms Page number 30>

 



  Relay 54 trips relay 68. Relay 68 trips relay 58. Relay 58 trips relays 70, 64 and 69 and also trips relays 55 and 76, if these are actuated. Relay 64 triggers relays 60 and 61. Relay 69 triggers relay 79 and also relay 78, if the latter is actuated. The triggering of the relay 70 disconnects the signaling battery B1 from the upper signaling conductor of the auxiliary line T1, thus causing the triggering of the relay 190.

   Triggering of relay 190 opens the circuit through the winding of relay 201, causing it to trigger, triggering of relay 205, if it is actuated, and triggering of relay 251 of the auxiliary line circuit IT2, if the auxiliary line Tl has been extended to the auxiliary line IT2, or the tripping of relay 225 if the auxiliary line Tl is extended only to the selector TS2, or the tripping of the line relay of any other selector, auxiliary line or suburban line to which the auxiliary line T1 is connected. Triggering of relay 201 triggers relay 202. Triggering of relay 202 triggers relay 200, triggers relay 207, if the latter is actuated, and reactivates relay 219.

   The relay 202 also disconnects the earth of the conductor 223., causing the trip of the relay 229 of the selector TS2, the trip of the corresponding relay of the selector AS2, and the trip of the relays 256 and 274 on a connection to the IT2 auxiliary line circuit. Triggering of relay 229 causes selector TS2 to return to the normal position, as described above. Relays 272 and 273 remain activated until lead C2 is disconnected from jack J7.

 <Desc / Clms Page number 31>

 



   If while dialing a suburban route number, a suburban route selector, such as TS2 or AS2, or a suburban train selector in a local automatic office, to which the connection is extended, encounters a situation in which all the auxiliary lines are occupied, the relay 55 is alternately actuated and tripped for '. turn on the FL lamp.

   Assuming that it is the selector TS2 which finds all the auxiliary lines occupied or at a chosen level, the springs of the "11th step of rotation" are actuated, by disconnecting the coil of the relay 229 from the conductor 223, by disconnecting the conductor 224 of resistor 220 to trigger relay 219, and connecting switch I to conductor 224 to cause intermittent operation of relay 211. Relay 211 causes alternate operation and tripping of relay 90, and relay 90, in turn, causes the operation and alternate tripping of relay 55 to ignite lamp FL.

   If the selector, which encounters a situation in which all auxiliary lines are busy, is arranged to park at a busy level and to wait for an auxiliary line to become free, relays 90 and 55 are alternately actuated and tripped in a similar manner, but at a different speed. The operation of the relay 55 causes the operation of the relay 57, and the relay 57 is blocked by a subsequent contact of the relay 66 to earth to a previous contact of the relay 69.

   Relay 57 connects the battery to the actuating winding of relay 70 to prevent it from further tripping under control of the D-dial pulse contacts, so that

 <Desc / Clms Page number 32>

 further pulses will not be sent on the auxiliary line T1 in case another digit is sent by means of the dial before the operator takes note of the park signal. The operator then returns the conversation and dial keys to the normal position, triggering relay 78 and actuating relays 66 and 76. Actuation of relay 66 trips relay 57 and relay 76 keeps relay 70 actuated. A selector designed for American parking is disclosed in / patent 2,097,165, issued to R.L. Stokely, October 26, 1937.

   When an auxiliary line becomes free, the signal is changed and the operation of the talk and dial keys causes the dial to be reassociated with the auxiliary line OT1, as described above. Dialing the number 1 will then send an impulse to the selector in question and thus begin its search operation for the auxiliary line. Any additional digit of the suburban road number can then be dialed and relay 70 will repeat the dial pulses.



   As the auxiliary line T1 can be seized by suburban route selectors, such as AS1 at one end and AS2 at the other end, it is necessary that the two-way auxiliary line circuits TWT1 and TWT2 and the auxiliary output line circuits OT1 and OT2 are arranged to establish the circumstances of occupation, which prevent the seizure by another selector or by an operator and to establish the required conditions of control of the complements or artificial lines of complement and the signaling through the circuit. To illustrate these operations, it is assumed that an auxiliary line T3 is entered by a suburban operator in a third office.

   The associated composite signaling circuit

 <Desc / Clms Page number 33>

 CS2, two-way auxiliary line circuit TWT3, auxiliary output line circuit OT3, and input suburban route selector TS3 are similar to corresponding circuits CS2, TWT2, OT2 and TS2 associated with auxiliary line T1 , and the operations resulting from the seizure of the auxiliary line T3 and dialing, are similar to those described above with regard to the incoming call by the auxiliary line T1.



  It is further assumed that the input suburban route selector TS3 is operated to choose an auxiliary suburban route selector AS2 and that the AS2 selector is operated to choose the auxiliary line T1. When extending the connection of the line . auxiliary T3, through the AS2 selector brushes to conductors 191, 192, 193 and 194, holding earth potential is connected to conductor 193, a ground from the front contact of the signaling relay in the composite signaling circuit CS3 is connected to the conductors 191 and 192, and a ground, through the intermediary of the relay windings in the circuit TWT3 corresponding to the relays 207 and 219 in the circuit TWT2, is connected to the conductor 194, all these devices being connected in a similar manner. - earth connection to the conductors 241, 242,

   243 and 244 of the input auxiliary line circuit IT2, during the call described above. Connecting the earth potential to conductor 193 closes circuits to actuate relay 215 of the two-way auxiliary line circuit TWT2 and relay 156 of the auxiliary output line circuit OT2. Relay 215 locks at conductor 193, connects relay 218 to conductor 195, and disconnects the windings of relays 200 and 201 from conductor 195. Relay 156 connects the battery to the socket of jack 5 and actuates relay 160. The relay

 <Desc / Clms Page number 34>

 160 closes a circuit to turn on the BL5 occupancy lamps.

   The connection of the earth potential from the previous contact of the signaling relay of the CS3 circuit, through the circuits TWT3, TS3 and AS2, to the conductors 191 and 192, is extended by the rear contacts of the relay 200, the conductors 181 and 182, the windings of the delay coil 180, the posterior contacts of the relay 161, the windings of the relay 205, the conductor 196, and the posterior contact of the relay 200, to the actuating winding of the relay 210. Ground connection to conductor 194 causes actuation of relay 217 of the two-way auxiliary line circuit TWT2, and relay 217 locks by its winding greater than the holding earth potential on conductor 193.



   Operation of relay 210 disconnects ground from resistor 175 and connects the battery, through this resistor 175, to delay coil 189, thereby causing signaling relay 91 to operate at the other. end of the auxiliary line T1. Operation of relay 90 connects earth to conductor 95 to cause the operation of relays 100, 101, 102 and 105 of the auxiliary line circuit, two-way TWT1 and operation of the line relay ( not shown) of selector TS1. Relay 100 connects ground to conductor 93 to protect the two-way auxiliary line circuit TWT1 from being selected by an auxiliary suburban route selector, such as AS1. The connection of the earth to the conductor 93 also causes the successive operation of the relays 56 and 60.



  Relay 56 connects the potential of the battery to the socket of jacks Jl, to indicate that this auxiliary line is busy, and relay 60 closes the circuit for

 <Desc / Clms Page number 35>

 switch on occupancy lamps BL1, The connection between earth at the front contact of signaling relay 90 and conductor 95 is maintained by a front contact of relay 56, although the normal connection is open at the rear contact of relay 60. The Relay 56 also opens the repeater termination, comprising a capacitor and resistor which are normally connected through leads 61 and $ 2, to prevent hissing from the voice frequency repeater (not shown). The operation of the suburban route selector TS1 and an auxiliary selector AS1 is similar to that of the selector TS2 described above.

   The above-mentioned operation of relay 217 causes the relay to trip.
183 and the operation of relay 184 to short-circuit the P3 and P4 complements. The response monitoring is received on the auxiliary line Tl by the relay
190. Operation of relay 190 closes a circuit including a previous contact of relay 215, to actuate relay 218.

   Relay 218 opens its operating circuit, locks to earth on conductor 193 and opens the operating circuit of relay 217, When relays 215 and 218 operate, the earth connection through the front contact of relay 190 and the conductor 195 is extended by the conductor 194, the selectors AS2 and TS3, the rear contacts of the relays in the two-way auxiliary line circuit TWT3, which correspond to the relays 219 and 215 of the circuit TWT2, to the winding of the relay which corresponds to the relay 211, thereby transmitting the response monitoring signal, through the auxiliary line T3, to the calling operator.



   For calls arriving by the main line Tl and extended by the selectors TS2 and AS2 to an auxiliary switching line leading to a local office.

 <Desc / Clms Page number 36>

 cal, there is no relay in the auxiliary line output circuit of the switching auxiliary line corresponding to relay 256 of the auxiliary input line circuit IT2. Therefore, the relay 219 of the two-way auxiliary line circuit TWT2 trips as soon as the selector AS2 seizes the auxiliary switching line. Triggering of relay 219 connects conductor 224 to the coil of relay 211, to actuate that relay, when the called subscriber in the local office answers.

   During such a call, the relay 207 is not actuated and the complement control relay 183 is kept actuated, so that the supplements P3 and P4 remain in the conversation circuit.



   Although the two-way auxiliary lines T1 and T3 are shown and described as being arranged for composite signaling, it is obvious that any type of signaling can be employed. Thus, in the arrangement shown in figure 9, a suburban auxiliary line T5 terminates in a signaling circuit SC5 arranged for signaling at voice frequencies, and the auxiliary line circuit: in two directions TV1T5 is provided with two polarized differential relays, controlled in a simple circuit comprising the conversation conductors in parallel.

   One of these two relays is actuated by a simplex imbalance, which causes more current in one side to control the transmission complements, and the other relay is actuated by a simplex imbalance, which causes a more intense current in the other side in order to control the repetition of the input voice frequency pulses according to the type of signaling provided in the auxiliary line or output line, to which the connection is extended.

 <Desc / Clms Page number 37>

 



   In the following description, it is assumed that the auxiliary line T5, the signaling circuit SC5 and the two-way auxiliary line circuit TWT5 are associated, with an output auxiliary line circuit and a suburban route selector, similar. to the auxiliary line circuit OT2 and to the selector TS2 shown in figure 7.



   When the main line T5 is seized at its far end, and when voice frequency signaling current is transmitted on the auxiliary line T5, as a seizing signal, the relay 390 is actuated.



   Relay 390 closes a circuit to actuate the relay
385. Relay 385 closes a circuit to actuate slow-acting relay 386, and closes a circuit from earth to the rear contact of relay 386, passing through the front outside contact of relay 390, the front, upper contact. and inside the relay
385, the rear contacts of relays 158 and 160 of the associated auxiliary output line circuit, the conductor
195, the posterior contacts of relays 315 and 324, the posterior and lower contact of relay 302, and resulting in the winding of relay 300.

   Operation of relay 300 opens the operating circuit, normally closed, through the winding of slow-tripping relay 320, and closes a circuit for actuating relay 301 and relay 225 of the selector circuit. associated suburban road trier TS2. The / actuation of relays 301 and 225 starts from the earth at the rear contact / of relay 386.

   passes through the front and outer contact of relay 390, the front, upper / inner contact of relay 385, the rear contacts of relays 158 and 160, conductor 195, rear contacts of relays 315 and 324, the winding relay

 <Desc / Clms Page number 38>

 
301, a rear contact of relay 316, the rear contact of relay 324, the winding of the marginal relay 306, a front contact of relay 300, then, in simplex, by resistors 321 and 322, the windings of relays 306 and 323, the rear contacts of the relay
161, the windings of the delay coil 180, the conductors 181 and 182, the front contacts of the relay 300, the conductors 221 and 222, the resistors
231 and 232, and then by resistor 230 and the coil of relay 225.

   Being marginal, relay 306 does not work. Relay 301 closes a circuit to actuate slow tripping relay 302. When relay 302 operates, relay 300 is kept actuated in series with resistor 304 under the control of two relays 301 and 302. Operation of the relay
302 closes the blocking circuit for relay 385 and connects the earth to the rear contact of relay 316, to the conductive body 223 of the associated selector TS2, in order to control the tripping of this one and of the following selectors. slow operation, the relay
386 does not open its posterior contact until after the si-
Gnal outlet is complete and relay 390 is triggered. When relay 390 triggers, it connects the earth, through its rear contact and the upper front internal contact of relay 385,

   to keep relays 201 and 225 activated. Relay
302 also closes a circuit to actuate the relay
325 slow release. Slow-trip relay 320 is normally actuated, bypassing resistor 322, so that by the time relay 300 operates, the simplex is unbalanced and the current, which is flowing through the lower windings of the 305 polarized differential relays. and 323 is more intense

 <Desc / Clms Page number 39>

 than the current, which passes through the upper windings.



  Relay 305 is then energized in one direction to keep its armature in the normal position, but relay 323 is energized in one direction, which brings its armature to its middle position. When relay 320 trips as a result of operation of relay 300, the short circuit around resistor 322 is opened and causes relay 323 to trip. As relay 323 trips before slow-operating relay 325 does. has operated, relay 324 also trips. The aforementioned operation of relay 302 also opens a normally closed circuit passing through resistor 303, the coil of relay 319 and the upper coil of relay 307. Relay 319 is thus normally actuated, but relay 307, which is marginal, does not work.

   When relay 302 operates, relay 319 is kept actuated in series with conductor 224 and resistor 220.



   When the signaling relay 390 responds to the first dial pulse train of the tone current arriving through the auxiliary line T5, the relays 301 and 225 are alternately triggered and reactivated. Slow-tripping relay 302 remains actuated while relay 301 responds. TS2 selector is activated, as described above, to select the desired group and a free auxiliary line in that group, after which relay operation. 229 extends the connection to the selected auxiliary suburban route selector.

   The AS2 selector is then controlled by the response of relay 390 to the second train of pulses arriving through the auxiliary line TS to select a desired group of auxiliary lines and after seizing a free auxiliary line in the selected group. , the connection is extended A, up to this auxiliary line.

 <Desc / Clms Page number 40>

 



   If the chosen auxiliary line is an input auxiliary line circuit, such as IT2, the operation is similar to that described above during the call arriving through the auxiliary line T1 to the auxiliary line circuit IT2. Relay 307 is actuated and maintained relay 319 actuated in series with the lower winding of relay 256 of auxiliary line circuit IT2. Relay 307 blocks under control of relay 302 and opens the normally closed circuit to actuate supplement control relay 383. When the call is answered, connecting ground to conductor 244 causes relay 319 to trip and actuation of response monitor relay 311. Relay 311 closes a circuit to actuate relay 387 of signaling circuit SC5.

   Relay 387 closes a circuit to actuate slow-acting relay 388. When relay 387 operates and until relay 388 operates, a circuit is closed to actuate relay 389. While relay 389 is actuated, the VF signaling current source is connected to the auxiliary line conductors. T5 to transmit to the calling office a response monitoring signal. If the connection is extended, through a C2 cord, to a tributary line or auxiliary line, the simplex circuit is unbalanced to cause the operation of the polarized differential relay 305, but, if the connection is extended, by the intermediate of the C2 cord, to a suburban line, the simplex is balanced and the relay 305 does not work.

   If relay 305 works, relay 383 is kept actuated and the transmission complements remain in the connection, but, if relay 305 does not work ... relay 383 trips and

 <Desc / Clms Page number 41>

 relay 384 operates to short-circuit the transmission complements. Reminder signals can be transmitted over the auxiliary line T5 in both directions. If a callback signal is transmitted from the calling office, the momentary operation of relay 390 in response to this signal causes relays 301 and 251 to momentarily trip, but relay 390 trips and relay 301 kicks in. before the relay 302 trips, and therefore the relay
302 keeps relays 385 and 386 actuated.

   If a responding operator transmits a callback signal, watchdog relay 311 is momentarily tripped, performing momentary tripping of relay 387 and momentary operation of relay 389, to connect the VF source to auxiliary line T5. Relay 388 is slow tripping and remains actuated, and when relay 387 comes on, relay 389 trips. If the answering operator disconnects before the calling operator disconnects, tripping of relays 272 and 273 of the IT2 auxiliary line circuit causes relay 255 to operate, connecting the battery to the two conductors of the simplex to cause fault. operation of marginal relay 306 of the two-way auxiliary line circuit calling TWT5.



   Operation of relay 306 closes a circuit to actuate relay 316. Relay 316 locks up under control of relay 302, closes the holding circuits for relays 300 and 311, opens the simplex circuit to trigger relays 301, 306 and 251, and disconnects the holding earth potential of the conductor
223 to trigger the triggering of the associated suburban route selector and the triggering of the auxiliary suburban route selector AS2, by which the connection to the auxiliary line circuit IT2 has been established,

 <Desc / Clms Page number 42>

 and to cause the return to normal position of the auxiliary line circuit IT2. Tripping of relay 311 causes tripping of relay 302, and tripping of relay 302 causes tripping of relays 316, 307 and 311.

   Relay tripping
311 causes relays 387 and 388 to trigger and relay 389 to operate momentarily to send the calling office a disconnect signal. Triggering relay 316 closes the circuit to actuate auxiliary line circuit relay 301 and the relay.
225 of the associated suburban route selector. Relay
301 returns relay 302 to action before the relays
325 and 385 have both tripped, so that relay 385 is kept actuated and signaling circuit SC5 is ready to repeat the dial pulses of another route number called to selector TS2 and to a auxiliary selector AS2, without the auxiliary line T5 having been triggered and re-entered by the calling operator.

   As the relay 388 is slower to trigger than to activate, the disconnect / signal of longer duration than the tap signal. When a disconnect signal is received by the auxiliary line T5 from the calling office, the relay 390 is actuated for a sufficient time to cause the triggering of the relay 251 and of the two relays 301 and 302. The triggering of the relay 302 causes the tripping of relays 385 and 386, the tripping of the selectors TS2 and AS2, and the tripping of the auxiliary line circuit IT2.



   If, during the call coming from the auxiliary line
T5, the selected auxiliary suburban route selector AS2 is operated to extend the connection to a two-way suburban auxiliary line circuit, such as
TWT2, the operations of the TWT5 and SC5 circuits are

 <Desc / Clms Page number 43>

 similar to the operations described above during the call transmitted to the auxiliary line circuit IT2.



   Assume now that the two-way auxiliary line circuit TWT5 is chosen and entered by one. AS2 suburban route auxiliary selector when a call arrives via an auxiliary line such as T1, arranged for composite signaling. In this case the holding earth potential is connected from the circuit TWT2 by the conductive bodies 223,193 and 393 to actuate the relay 315 of the auxiliary line circuit TWT5 and to protect the selected auxiliary line from being taken by another. selector. The relay 315 is blocked directly to the conductor 393 and causes the triggering of the normally actuated relay 320.

   The relay 317 of the auxiliary line circuit TWT5 is actuated by the current in a circuit from the battery, passing through its lower winding, the lower rear contact of the relay 318, the conductor 394, the selector AS2, the brush 238 and the conductor 224 of the selector TS2, the rear contact and the winding of the relay 219 of the two-way auxiliary line circuit TWT2 of the calling auxiliary line T1 and the upper winding of the relay 207, and ending in the land.



  The relay 207 is also actuated by the current of this circuit and the relay 219 is kept actuated. Relay 317 connects, through its upper winding, to the holding earth potential on conductor 393, and relay 207 locks, through its lower winding, under control of relay 202. When relay 317 operates, the circuit d The actuation of the relay 383 is open, the relay 383 trips, the relay 384 operates and the complements or artificial lines of complement of transmission are short-circuited. The operation of

 <Desc / Clms Page number 44>

 relay 207, places the complement control relay 183, under the control of relay 205.

   Another circuit, closed after the socket of the auxiliary line circuit TWT5, starts from the battery, passes through the winding of relay 310, a rear contact of relay 300, then in a simple manner, through resistors 321 and 322 , the two windings of the differential relays and with opposite polarities 305 and 323, by the rear contacts of the relay 161 and the windings of the delay coil 180 of the auxiliary output line circuit OT2 associated with the by calling auxiliary line T5, the rear contacts of relay 300, conductors 391 and 392, the changeover conductors of selectors AS2 and TS2, conductors 221 and 222, the front contacts of relay 200, conductors 181 and 182, the windings of the coil
160 delay / and the rear contacts of relay 161 of the OT2 auxiliary line circuit,

   associates with the calling auxiliary line, the two windings of relay 205, the conductor 196, the front contact of the relay 200, the winding of the relay 206, the rear contact of the relay 216, the winding of the relay 201, the con - posterior tact of relay 215, conductor 195, front contact of relay 156, rear contact of relay 158 and ends at earth at the front contact of signaling relay 190. Relay 201 is kept actuated and relay 310 is actuated by the current flowing in this circuit. The moment this circuit is closed for the first time, the simplex is unbalanced because resistor 322 is shorted by normally actuated relay 320. For this reason, relay 323 can be momentarily actuated.

   Momentary operation of relay 323 may cause relay 324 to operate, but relay 324 cannot block.

 <Desc / Clms Page number 45>

 since relay 325 is not actuated. When the short circuit around resistor 322 is opened by tripping of slow tripping relay 320, the simplex is balanced and relays 323 and 324 trip. The relays 205 and 305 do not work, because the differential excitation of these polarized relays, before the simplex / is balanced, is done in one direction in order to keep the armatures in the normal position.

   When relay 205 is normal and relay 207 operates, complements control relay 183 trips, mail 184 operates, and complements P3 and P4 are short-circuited. The aforementioned operation of relay 310 after taking the auxiliary line circuit TWT5 closes a circuit from the battery, and passing through the resistor 175 of the auxiliary line circuit of associated output, the subsequent current of the relay 324, the front contact of relay 310, the rear contact of relay
 EMI45.1
 3 s W g-o.o.rG-ax.xe. ¯d di. ¯, 14 T-. -caxi.ta.c.t-pasté 170 of the output auxiliary line circuit, and the winding of relay 387, Relay 387 operates by closing the circuits to actuate relays 388 and 389.

   Relay 389 connects the VF signaling source to the T5 auxiliary line to transmit a tap signal. When the slow-moving relay 368 operates, the relays 389 trips. When a response signal is received by the auxiliary line T5, relay 390 operates by closing the circuit to actuate relay 385. Relay 385 locks to ground at a previous contact of relay 315 and closes a circuit to actuate the relay. 386 slow running.



  When relays 390 and 385 operate and before relay 386 operates, earth is connected, through a rear contact of relay 386,

 <Desc / Clms Page number 46>

 front contacts of relays 390 and 385, a rear contact of relay 158 and a front contact of relay 156 of the associated auxiliary output line circuit, and through a front contact of relay 315, to winding of relay 318. After relay 390 trips at the end of the response signal, earth is connected through a rear contact of relay 390 and a front contact of relay 385, to the winding of relay 318. Relay 318 operates and locks at the holding earth potential connected to conductor 393.

   When relay 318 operates, the monitoring earth potential connected to conductor 395 is further connected, through the lower and front contact of relay 318, conductor 394, by selectors AS2 and TS2 to the conductor. 22L, thereby triggering relay 219. Triggering of relay 219 extends the monitoring earth potential, via conductor 224 and a posterior contact of relay 219, to the winding of relay 211 Relay 211 is actuated by the current flowing in this circuit, to transmit a response monitor signal through the calling auxiliary line, as described above.

   If a callback signal is received by the calling auxiliary line, the momentary tripping of relay 190 causes the momentary tripping of relays 201, 310 and 387, and relay 389 is momentarily actuated, to connect the VF source to
T5 the auxiliary line / in order to transmit a reminder signal. If a recall signal is received by the auxiliary line T5, the relay 390 is momentarily actuated, causing the momentary tripping of the relay 211, and the relay 211 transmits the recall signal through the auxiliary line T1, as described above. If the re-

 <Desc / Clms Page number 47>

 lais 390 is actuated by a disconnection signal entering through the auxiliary line TS, the relay 211 is triggered in the same way so as to send a disconnection signal through the auxiliary line T1.



  When a disconnection signal is received by the calling auxiliary line T1, the triggering of the relay 190 causes the triggering of the relay 310 and the triggering of the two relays 201 and 202, which disconnects the holding earth potential of the conductors 223. and 393, so as to cause the return to the normal position of the trigger switches TS2 and AS2 and of the auxiliary line circuit TWT2, as described above. Disconnecting the earth from conductor 393 causes the relays 315 and 317 to trip, and relay 307 to trip, if the latter is actuated. Triggering of relay 310 triggers the triggering of relays 387 and 388.

   After the tripping of relay 387 and before tripping of the slow tripping relay 388, the relay 389 is momentarily actuated, to connect the VF source; to the auxiliary line T5, in order to transmit a disconnection signal.



   Assume now that the two-way auxiliary line circuit TWT5 is chosen by an auxiliary selector AS2, when a call arrives through another suburban voice-frequency auxiliary line, similar to T5, through a signaling circuit and a signaling circuit. Auxiliary line with two directions, similar to signaling circuit SC5 and auxiliary line circuit TWT5. The two-way signaling and auxiliary line circuits associated with the auxiliary line from the calling suburban office are referred to below as calling circuits and circuits.

 <Desc / Clms Page number 48>

 associated signaling and auxiliary line baked goods. to the auxiliary line, terminating at the called suburban office, are called hereinafter called circuits.

   The operations of the calling two-way auxiliary line and signaling circuits are similar to those described above when a call arrives through the T5 auxiliary line, except in the cases mentioned below. Called auxiliary line and signaling circuits are similar to those described above, when these circuits are seized during a call arriving via the auxiliary line T1, except in the cases mentioned below.



  Although when the TWT5 auxiliary line circuit is taped, resistor 322 of the calling auxiliary line circuit is not shorted, resistor 322 of the called auxiliary line circuit is shorted. by a rear contact of relay 320 normally actuated. This is why the simplex is unbalanced and not only does relay 310 of the called auxiliary line circuit operate, but relay 323 in each of the connected two-way auxiliary line circuits is actuated.The operation of relay 310 of the called auxiliary line circuit causes the operation of relays 387 and 389, for source momentarily connect the @@@@@ VF to the auxiliary line T5,

   in order to transmit a tap signal When the normally actuated relay 320 of the called auxiliary line circuit trips and opens the short circuit around resistor 322, the simplex is balanced and the relay 323 of each auxiliary line circuit trips . Tripping of relay 323 of the called auxiliary line circuit causes relay 324 to trip, since relay 315 is actuated by an outgoing call But in the line circuit.

 <Desc / Clms Page number 49>

 auxiliary calling, the relay 324 is blocked at a previous contact of the relay already activated 325.

   When relay 324 of the calling auxiliary line circuit operates, the operating circuit of relay 301 is open, but relay 302 is kept actuated by a front contact of relay 324 and a rear contact of relay 315, to ground in the associated signaling circuit, as indicated above. Relay 324 of the calling auxiliary line circuit also connects ground, through the winding of relay 306 and the front and top contact of relay 300, to resistors 321 and 322, to keep the simplex closed so as to keep the relay 310 of the called auxiliary line circuit activated.

   When the called signaling circuit relay 390 is actuated by a response monitor signal from the called suburban office, it causes the called auxiliary line circuit relay 318 to operate and causes relay 319 to trip and operate. of relay 311 of the calling auxiliary line circuit. But since relay 324 is actuated, operation of relay 311 cannot cause relays 387 and 389 to operate. The voice frequency response signal, the callback signals; and a disconnect signal from the called office are transmitted over the chat connection to the calling suburban auxiliary line.

   The operation of the relay 390 of the called signaling circuit, in response to the callback or disconnection signals from the called office, causes the operation of the Bêlais 311, without causing the operation of the relays 387 and 389. Callback signals received from the called office calling office are transmitted over the chat connection to the called suburban auxiliary line.

   The operation of relay 390

 <Desc / Clms Page number 50>

 caller signaling circuit, in response to a ring or call signal from the calling office causes the holding circuit to momentarily open for relay 302 of the calling two-way auxiliary line circuit, but relay 302 is at slow tripping and stays actuated A disconnect signal from the calling suburban office is transmitted, over the talk connection, to the called suburban office and also causes the calling signaling circuit relay 390 to operate for an interval long enough to cause the call. triggering of relay 302.

   Tripping of relay 302 of the calling auxiliary line circuit causes relay 300 of the calling auxiliary line circuit to trip and tripping of relay 310 of the called auxiliary line circuit. All circuits and switches involved in the connection between the calling and called suburban auxiliary lines are then brought back. in normal position.



   CLAIMS
1. Telephone system comprising a plurality of lines and a selector for establishing a connection between at least two of the lines, characterized in that it comprises signaling means for changing a characteristic of the connection, in order to provide a signal of control.


    

Claims (1)

2. System according to claim 1, characterized in that the signaling means comprise means: for unbalancing the connection. 3. System according to claim 2, characterized in that it comprises a differential relay operating in response to the unbalance of the connection. <Desc / Clms Page number 51> 4. System according to either of claims 2 and 3, characterized in that the lines comprise an incoming line, with which the differential relay is associated, and outgoing lines, the selector having the effect of: to establish a connection between the incoming line and any of the outgoing lines, the connection forming a simplex circuit comprising the windings of the relay and the talk leads of the selector. 5. System according to claim 4, characterized in that it comprises signal receiving means for repeating signals going from the incoming line, via the simplex circuit, to the outgoing line. 6. System according to one or the other of the claims 4 and two tions / 5, characterized in that it comprises / polarized differential relays associated with the incoming line, the simplex circuit comprising the windings of the two differential relays, the signaling means comprising means associated with the line outgoing and intended to decrease the resistance on one side of the simplex circuit to cause the operation of one of the polarized differential relays and means for reducing the resistance on the other side of the simplex circuit, to cause operation on the other, polarized differential relays. 7. System according to either of the preceding claims, characterized in that it comprises a marginal relay operating in response to a predetermined level of resistance of the connection. 8. System according to claim 7, characterized in that the signaling means comprise means for changing the resistance of the connection in order to actuate the marginal relay. 9. System according to claim 1, characterized <Desc / Clms Page number 52> in that the selector comprises conversation conductors, a conductor with a socket or conductive body and a fourth conductor, the lines comprising an incoming line and groups of outgoing lines accessible to the selector, signal receiving means associated with the incoming line, a simplex circuit comprising the talk leads for repeating direction signals, received by the signal receiving means, at the selector, means in the selector responsive to the signals for selecting the desired group of outgoing lines - aunts and to select a free line in the selected group, a complement or resistance network connected to the input end of the line, a complement control relay to close and to open a short circuit around the complement, a normally effective circuit to control the complement control relay, in order to open the short circuit, a circuit comprising the fourth selector conductor and intended to control the complement control relay, when selecting a line and depending on the character of the line, a circuit comprising the fourth conductor and intended to transmit monitoring signals from the selected line to the incoming line, a circuit including a differential relay in the simplex circuit and intended to control the control relay of the complete, while the fourth conductor is used to transmit supervision signals. 10. System according to claim 1, characterized in that the lines comprise an incoming line and outgoing lines, the selector comprising conversation conductors for connecting the incoming line to any of the outgoing lines, associated signal receiving means. to each of the outgoing lines, means <Desc / Clms Page number 53> associated with the incoming line and intended to receive the signals arriving via the incoming line and to repeat the signals received by means of signal receivers associated with the outgoing line connected thereto, the circuit for repeating the signals comprising the conversation conductors connected in parallel, and a differential relay associated with the incoming line and intended to receive monitoring signals coming from the connected outgoing line, the relay having one of its windings connected in series to one of the conversation conductors and another of its windings connected in series to the other of the conversation conductors. 11. System according to claim 10, characterized in that the signaling means comprise means associated with the outgoing line connected and intended to increase the current passing through one of the conversation conductors, to cause the operation of the relay. 12. System according to either of claims 10 and 11, characterized in that a marginal relay is associated with the incoming line, the winding of the marginal relay being connected in series to the two conversation conductors. 13. System according to claim 12, characterized in that the signaling means comprise means associated with the outgoing line connected and intended to increase the current flowing through the two conversation conductors, to cause the operation of the marginal relay. . 14. System according to claim 10, characterized in that the relay is a polarized differential relay. 15. System according to claim 14, characterized in that it comprises a second polarized differential relay associated with the incoming line and intended to receive <Desc / Clms Page number 54> monitoring signals from the connected outgoing line, the second differential relay having one of its windings connected in series to one of the conversation conductors and another of its windings connected in series to the other of the conversation conductors. 16. System according to claim 15, characterized in that the signaling means have the effect of increasing the current flowing through one of the conversation conductors, to actuate one polarized relay, and passing through the other. conversation lead, to actuate the other polarized relay. 17. System according to claim 1, characterized in that the connection comprises conversion conductors, a holding conductor and a fourth conductor, the lines comprising an incoming line, with which are associated complements or artificial lines. additional transmission lines, and groups of outgoing lines, the selector having the effect of connecting the incoming line to a desired line of the groups of outgoing lines, a complement control relay and a normally actuated relay associated with the incoming line and connected in series to the fourth conductor, a circuit associated with the outgoing line chosen if it is in one of the groups, to activate the complements control relay and keep the relay normally activated, a circuit, associated with the chosen line, if it is in another of the aforementioned groups, to keep the relay normally activated without activating the control relay complements, subscriber stations, means for establishing the connection between the incoming line, via the selected outgoing line, and the station of the called subscriber and for signaling the called station, a circuit associated with the outgoing line selected in one or the other of the groups, and intended <Desc / Clms Page number 55> to trigger the normally actuated relay when the call is answered by the called station, and a monitoring relay associated with the incoming line, the triggering of the normally actuated relay having the effect of cutting the fourth conductor of the windings of the normally actuated relay and of the complement control relay and of connecting the fourth conductor to the winding of the control relay. 18. System according to claim 17, characterized in that it comprises a signaling relay associated with the incoming line and intended to receive incoming signals, a line relay associated with the selected outgoing line, and a simplex circuit germinated by them. Conversation conductors between the incoming line and the selected outgoing line, to repeat the signals received by the signal relay from the line relay. 19. System according to claim 1c, characterized in that it comprises a differential complement control relay, one of the windings of which is in series with one of the conductors of the simplex circuit and the other winding in series with the other conductor. of the simple circuit, and a circuit associated with the selected outgoing line and intended to unbalance the simplex circuit, to cause the operation of the differential control relay of the complements. 20. System according to claim 1, characterized in that one of the lines constitutes a suburban auxiliary line and the others a suburban auxiliary line circuit terminating at an operator position having a cord, signal receiving means. associated with the auxiliary line, and intended to receive direction and monitoring signals entering through the line, the selector being controlled by the direction signals received by the signal receiving means for connecting the auxiliary line to the auxiliary line circuit, a cir- <Desc / Clms Page number 56> simplex baked comprising the selector conversation conductors and intended to transmit monitoring signals from the signal receiving means to the auxiliary line circuits, a circuit including a selector non-talk lead for transmitting a supervisory / answer signal) through the auxiliary line when connecting the cord to the auxiliary line circuit for answering the call, and a circuit including a marginal relay in series with the two conductors of the simplex circuit and intended to return the selector to the normal position, when the auxiliary line circuit cord is disconnected. 21. System according to claim 20, characterized in that the marginal relay transmits a disconnection signal via the auxiliary line. 22. System according to claim 1, characterized in that it comprises an operator's position comprising a cord, a dial, and a jack, one of the lines constituting an auxiliary line, other lines constituting a junction to connect the auxiliary line to the jack, a relay transmitting signals in the auxiliary line circuit, means responding to the connection of the cord and the jack and intended to actuate the relay transmitting the signals so that it transmits a tap signal through the auxiliary line , means comprising a key in position for operatively connecting the dial to and through the conversation conductors of the cord to the signal transmission relay, a circuit comprising a relay in the auxiliary line circuit made effective by connecting the dial to the cord to place the signal transmitting relay under the sole control of the dial, the signal transmitting relay then being effective to repeat dial pulses through the <Desc / Clms Page number 57> auxiliary line, a cut-off relay in the auxiliary line circuit to disconnect the signal transmitting relay from the talk conductors of the auxiliary line circuit and to close a connection. conversation between the cord and the auxiliary line, a circuit comprising the socket conductors or peripheral conductors of the cord and the auxiliary line circuit to control the signal transmitting relay: after operation of the cut-off relay, and a circuit comprising a relay in the auxiliary line circuit connected to one of the conversion conductors of the cord to cause the cut-off relay to trip, in response to the reactivation of the means for connecting the dial to the aforementioned position. 23. System according to claim 22, characterized in that the cut-off relay closes a simplex circuit comprising the conversation conductors of the resistance complement cord for the auxiliary line or junction line, a complement control relay in series with the simplex circuit and a relay in the auxiliary line circuit in series with one of the conductors of the simplex circuit, to trigger the cut-off relay in order to place the signaling relay again under the control of the dial, in response to the reactivation of means for connecting the dial to the position of the operator. 24. System according to claim 1, characterized in that it comprises means for repeating direction signals arriving via one of the lines at the selector, comprising a circuit comprising the con- versation conductors in parallel, of the means in the selector. to select a group of lines corresponding to the signals and to enter a series of terminals in the <Desc / Clms Page number 58> selector means connecting the input series of terminals to a line constituting an auxiliary line or junction circuit, means comprising the conversation conductors of the selector group in parallel for repeating signals arriving by the line to the auxiliary line circuit, a network of resistance in series with a conversation conductor of the line, means comprising a relay for short-circuiting the network, and control means for the relay, the control means comprising the conversation conductors of the selector group in parallel and the conversation conductors of the auxiliary line or junction circuit in parallel . 25. System according to claim 24, characterized in that it comprises means comprising the conversation conductors of the group selector in parallel and the conversation conductors of the auxiliary line or junction circuit in parallel, to effect the return. selector switch to its normal position. 26. System according to claim 1, characterized in that it comprises a central office, one of the lines comprising a called line terminating at the central office, another line comprising an auxiliary line extending to the central office. , the connection comprising one or more conductors which delimit a path or control path and means controlled by this path for controlling the level of transmission of the voice current on the auxiliary line. 27. System according to claim 26, characterized in that a pair of conductors constitutes a communication channel and in that a third conductor defines the control path. 28. System according to one or the other of the claims <Desc / Clms Page number 59> tions 26 and 27, characterized in that the resistance of. control path varies between two values, in response to surveillance operations performed at the far end of the called line. 29. System according to claim 28, characterized in that it comprises means operating in response to the completion of the route when the called line is seized to change the level of transmission of the voice current by the main line, the latter means being blocked. after their operation, and means also operate in response to the completion of the path for transmitting a monitoring signal through the auxiliary line and then operating, in response to variations in the resistance of the path between the aforesaid values, for transmit additional control signals through the auxiliary line. 30. System according to either of claims 26, 27 and 28, characterized in that it comprises means for transmitting control signals over the controlled course, according to variations in the resistance of the course. 31. System according to either of claims 26 to 30, characterized in that a plurality of call lines and a plurality of connections are provided, each of the connections comprising one or more connections. - drivers defining a route or control route, extending to the central office terminus of the called line, the terminal impedances of the control routes being different for the different lines, and means controlled on said routes according to the requirements - final dances of these and intended to determine the level of transmission of the vocal current by the auxiliary line. <Desc / Clms Page number 60> 32. System according to claim 31, characterized in that the means for determining the level of transmission of the voice current by the auxiliary line comprise a relay, the winding of which is included in the common part of the various control paths, and which is selectively controlled according to the terminal impedances of the paths, and means controlled according to the adjustment of the relay, to control the level of transmission of the speech current on the auxiliary line. 33. System according to claim 1, characterized in that at least one of the lines extends to a central office, said system comprising a line circuit terminating the line in the central office, a communication device. mutation, the selector being arranged to establish a connection of the line, by the switching device, to a called line which is tarnished at the central office, the connection comprising a resistance bridge comprising in its arms the conversation conductors of the part of the connection extending between the line circuit and the switching device, and of the means, controlled according to the balanced or unbalanced state of the bridge, for determining the level of transmission of the speech current by the said line in the first place . 34. System according to claim 33, characterized in that the arms of the bridge, which include the conversation conductors, are progressively extended to each switching stage of the part of the connection. 35. System according to either of claims 33 and 34, characterized in that it comprises means controlled according to the designation of the telephone directory number of the called line, to determine the balanced or unbalanced state. - freed from the bridge. 36. System according to one or the other of the claims <Desc / Clms Page number 61> tions 33, 34 and 35, characterized in that it comprises means coming into action in the case where the connection is extended to a called line of a particular character, to unbalance the bridge.