BE367844A - - Google Patents

Description

       

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  PERFORMANCES TO TELEPHONE SYSTEMS FOR OFFICE AUTOMATIC OR SEMI-AUTOMATIC CENTRAL OFFICES
This invention relates to telephone systems using switched machines, and more particularly to systems in which, in addition to the ordinary service provided for the interconnection of subscriber lines, a means must be used for extend connections from an inter-city operator position or from a circuit supervisor's test terminal to subscriber lines.



   One of the aims of the invention is to provide arrangements assuring the said facilities to automatic or semi-automatic telephone systems of the type in which the

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 Conversation switches, in the digital switching stages, are actuated under the control of circuits, known as control circuits, each common to a series of conversation switches, but individual to a single switching stage.

   In systems of this kind, the same final conversation switches are used to extend ordinary calls and long distance calls, with means being provided, in the common control circuits associated with the final conversation switches, to perform various operations. on these switches and complete both types of connection. According to a further fact of the invention, in a system of the kind described, conversation switches are provided for establishing ordinary connections ot trunk connections, common control circuits, associated with them, being provided with means which exert a distinction. through.

   which, in the case of an ordinary connection, a ringing current is automatically applied to a requested line, but in the case of a long distance call, the connection is completed to the requested line without any application automatic Ronnerie current does not take place.



   In an automatic or semi-automatic telephone system, means is provided for establishing long distance calls, with the digital switch stages being operated under the control of circuits each common to a series of conversation switches, but individual single-stage switching, the same talkers being used to extend ordinary connections and toll connections.



   Special conversation switches can be provided to set up preference calls, for example calls from a long distance operator position or from a test table of a circuit supervisor, these special switches.

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 skies being adapted to be operated under the control of circuits which also serve to control the operation of the commu. Conversation timers used for regular calls.



   These facts, as well as others not especially mentioned herein, are best understood from the following description, taken in connection with the accompanying drawings. In this description, the invention is described as applied to a system using switches with mechanical action and single movement for the conversation muters and for the director switches of the control circuit.



   In the accompanying drawings, fig.l shows a subscriber line, a starting circuit, and a first line finder; fig.2 shows the circuit of a second line finder; FIG. 3 shows a circuit for a first group finder; the. f ig.4 shows a circuit for a second group finder; fig.5 shows a circuit for a final researcher; fig. 6 shows a control circuit for a first group finder; fig.7 shows a control circuit for a second group finder; fig.8 shows a control circuit for a final finder; Fig. 9 shows a recording circuit containing a recorder finder;

   fig.10 shows a set of relays for incoming trunk lines with two conductors; FIG. 11 shows an operator position for special services; fig.12 shows equipment for intercity trunk lines, and in the upper left corner a cord circuit, for intercity switchboard; fig. 13 shows a junction equipment for the circuit supervisor and for the trunk operator, as well as in the upper left corner a cord circuit for an interurban panel and a position of circuit supervisor; FIG. 14 shows a circuit for the final test finder of the circuit supervisor and the trunk operator;

   FIG. 15 is a diagram showing schematically a system of the kind envisaged.



   A general description is first given with reference to

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 rant in Figure 15.



   When the telephone is removed from the hook switch at station S, the calling line is extended through line finders, primary and secondary, LF1 and LF2 to a primary finder of groups 1GF having an associated free control circuit. ICF. Immediately after the circuit comprising the secondary line finder LF2 and the butt finder 1GF, is connected to a free recorder circuit RC through a recorder finder PR. An auditory signal to operate the dialing disk is sent to the calling subscriber.



   The subscriber operates his disc with the usual material.



  The first digit marked advances the primary digital switch of the recording circuit to a corresponding position.



  When the first digit has been received, a signal is sent to the front of the recording circuit so that the primary IGF group finder switch, associated with the LF2 line finder, connects with its control circuit, including the switch. ICF finder will turn to find the IGF switch.



  The ICF control finder then advances to a position corresponding to the first digit marked on the disk, and in that position it marks the requested group of connection circuits partart of the IGF switch bank. During the last mentioned movement, reversible pulses are returned from the ICF finder to count down the primary digital switch in the RC recorder circuit. The primary IGF group finder is now looking for a free junction circuit extending to a secondary 2GF group finder whose associated control circuit is free, and that in the group determined by the displacement of ICF.

   It should be noted that the arcing circuits of expensive group switches do not need to be arranged in a definite order, and furthermore the groups may not contain the same number of switching circuits. junction, If it is found necessary to increase the number of junction circuits in a group of parts

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 binding, this can be done without disturbing the existing connections, the additional junction circuits being connected in any reserve positions in the arcs.



   The rest of the connection depends on the kind of call that takes place. If it is assumed that the call considered is a local call, when the second digit is marked on the disc, a signal is still sent forward by the recorder circuit RC, which causes the secondary searcher of groups 2GF, which has been taken in use, to be connected to its control circuit, of which the 2CF researcher starts to turn to find the said engaged researcher 2GF.



  The apparatus' 2CB then advances to a position corresponding to the second digit marked, and marks the requested group of connection circuits in the bank of 2GF. During this movement, reversible pulses are fed back to the recorder circuit to count down the secondary digital switch. The 2GF seeker is now looking in the desired group for a free connection circuit going to a free final seeker FF whose associated control circuit is also free.



   When the third digit, or tens digit, and at least one impulse of the fourth digit, or units digit, have been received by the recording circuit, the final seeker FE control circuit is taken into use, and its FCF researcher searches until it finds FF. The FCF finder then advances to a position corresponding to the tens digit, and during this movement, reversible pulses are sent back to count down the digital tens switch. The final seeker FF now advances to the requested line, after which the FCF control seeker continues to advance to a position corresponding to the requested line.

   During this movement the final seeker FF follows the control seeker FCF, and a reversible pulse is sent to the digital switch that units for each position through which FCF passes.



   In addition to control the selections of the tens and

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 Units, the final control circuit determines whether or not the number called relates to an individual line or a P.B.X.



  For the latter case, all the cut-off relays of all the lines of a PBX group, except the last line, are provided with an additional contact through which a potential is applied to a corresponding terminal in the terminal. FCF control finder arc, when the line is busy. If the requested line corresponds to a P.B.X. whose first line is busy, FCF advances the final finder FF until a free line is found. In the event that all the lines in the group are busy, the ordinary busy auditory signal is sent to the calling line.



   It should be noted that the control circuits are not engaged until the recording circuit is ready to receive the corresponding reversible pulses. By this arrangement, the control circuits are kept in use only for the shortest possible time. In the event that all the connection circuits of a requested group are busy, the group searcher switches are arranged to continue searching for a determined time, for example ten seconds. If m free connection circuit is not found during this time, the recording circuit releases the control circuit and sends an auditory busy signal to the calling lines.



   It should also be observed that a control circuit finder has a dual function. It first leaves a normal position and causes the binding of a predetermined connection circuit to a final finder switch or to a group switch associated with the control circuit, after which it controls the finder maneuver. final or groups. For example, there are usually ten lead circuits, and their associated searchers, in a group served by a control circuit. If connection circuit No.6 was chosen from a previous connection step, the control circuit finder advances, and when

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 position six is reached, this junction circuit is attached.



   The control finder then continues to move forward and sends reversible pulses backward.



   All the switches in the conversation circuit are of the type without a home position, and when the connection is reestablished they remain in the positions to which they were last brought.



   The RC recorder circuit is arranged to serve special two-digit calls for which the numbers 01,
02, etc ... are reserved. These calls are forwarded to an OP operator position through a regular group primary seeker such as 1GF, and a special group secondary seeker such as
SGF controlled by an SCF control researcher. The LF2 line finder transmission bridge, IGF, is remote for these calls, and the calling line is mechanically connected to the manual cord circuit from which the talk battery is supplied. Such a connection remains under the control of the operator, and the subscriber cannot be released until the operator terminates the connection.



   False calls are also automatically transmitted to a similar operator position through two stages of group selection. The number "OO" is assigned for false calls, the recording circuit being automatically brought to these digits by earthed lines or if the disc maneuver has not taken place within thirty seconds. When a false call occurs, the current bypass is automatically removed from the line finder circuit so that the bridge relay is not overheated. The operator, by lowering a key, can cause a guard lamp of the LF2,1GF line searcher circuit to flicker, in order to indicate the searcher held by a false call.



   To extend long distance calls coming from a TB long distance operator position, trunk trunk lines are provided which include groups of TR relays and each other.

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 end up in primary researchers of TGF special groups.



  When a trunk line is used, it is connected to a regular RC recorder circuit. TGF group seekers are similar to regular group 2CF secondary seekers, The same 2GF group secondary seekers and FF end seekers are used to extend these calls, but when the RC recorder circuit is requested: in use by a circuit trunk trunk TR, this RC circuit is arranged to exert a distinction whereby the end finder FF suppresses the ringing current, so that the call of the last subscriber is entirely under the control of the operator. long distance, If the requested line is busy, the long distance operator receives the regular busy signal.



   TOB tables for the offer of interurban connections and WCB test tables of the circuit supervisor are planned to obtain access to junction circuits comprising groups of discrete relays and ending in the primary researchers of TWGF1 groups. When a trunk line is taken in use it is connected to a regular RC recorder circuit. A special train of primary and secondary group searcher switches and TWGF1, TWGF2, TWFF searcher switches are used to extend these connections. These TWGF1 and TWFG2 researchers are identical to the secondary researchers of 2GF regular groups, but they are not connected to the same multiple as the researchers of regular groups.

   The primary seekers of TWGFl groups, for the offer of trunk connections, are controlled by the same TCF control circuit as the primary seekers of groups for TGF trunk lines, while the secondary seekers of groups for the long distance connections are controlled by the same 2CF control circuit as the secondary researchers of regular 2GF groups. For each group of one hundred subscriber lines, a test TWFF final researcher

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 and supply is expected which differs from regular EF end seekers in that it is arranged to stop on the requested line without trying or ringing.

   These TWFF finders are adapted to be controlled by the same FCF control circuits as regular FF end finders.



   Two-conductor IJ trunks from remote offices terminate at IJR relay groups and JGF arrival group seekers controlled by circuits containing JCF control seekers. These group researchers and control circuits are identical to the 2GF local group researchers and 2CF control researchers. The IJR relay group incorporates a transmission bridge which is arranged to be cut and a metallic circuit substituted for it during
 EMI9.1
 1 'sTa.biissem ent of a connection.



   Various kinds of call facilities are now described in detail.



   Local call. When a subscriber removes his receiver to send a call, the line relay Ir (fig.l) is energized through the circuit of the subscriber's set. This relay Lr, by energizing, places a battery potential on the multiple test terminals of the first line seekers, and closes a circuit for the common starting relay Fsr which energizes and closes the circuits of the relays. Asr. These close the circuits of the electromagnets PF of all the primary searchers of free lines in series with the relay Lgr through the contacts Ltr2 and Lhr3. If there is no free researcher in the group, the Lgr relay remains deactivated and an LGL guard lamp lights up.



   When a seeker reaches the calling line, for example the seeker shown, the test relay Ltr energizes through its right-hand winding to: mute resistance, opening on contact Ltr2 the circuit of the electromagnet PL and closing on the Ltrl contact a circuit for the Lhr relay through its right winding and the common starting relay Csr of a subgroup of researchers

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 secondary lines. The Ltr relay also connects the battery to the multiple test terminals of the secondary line researchers. The Lhr relay, at the Lhrl contact, connects the low resistance left winding of Ltr in parallel with its right high resistance winding, which causes the resetting of Fsr which neutralizes the Asr relays, to stop the primary line seekers remaining.

   The group of secondary line seekers is divided into four subgroups, the arrangement being such that only the free seekers of a subgroup are activated for a call, but in the event that all seekers of that subgroup are engaged, the free seekers of the next subgroup are put into action, and so on.



   The Car relay, of the first sub-group, energizes an auxiliary relay Hsr which energizes one or more Bsr start relays of the sub-group and prepares a circuit for the auxiliary Hslr relay of the following sub-group. The Bsr and- Hsr relays close motor circuits in parallel for free researchers: from the first sub-group through a common Sgr relay. If no seeker is free in this sub-group, the slow-acting relay Abr 'is energized and closes the circuit of the Car and Hslr relays of the second sub-group in which free seekers are selected as a result of the excitation of the Bsr relay.

   It is easy to see that if no seeker is free in the second subgroup, the start relays of the third subgroup are energized, and so on until all four subgroups are in action. If no seeker is free in the four groups, an SGL supervision lamp is ignited by a circuit extending through the work contacts of the Abr relays of the last three subgroups.



   The pilot relay Sgr. is adjusted to operate through a single motor circuit. If desired, this relay can be set so that it does not operate unless two, three etc ... motor circuits are closed, and in this case a second sub-

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 group is activated if only two, three, etc .... seekers are free in the first subgroup.



   In the secondary finder of fig.2, the motor electromagnet PL is excited through a circuit passing through the contacts Arl, Frl, Cr3, and Dr2. When a secondary line finder has found the primary line finder, the test relay is energized through its left high resistance winding, towards earth at the Ecirl contact of the control circuit, fig. 6, serving the primary researcher of. groups fig.3 linked to the secondary researcher. If the control circuit fig.6 is associated with another group finder, the relay Ecir is energized as described, and therefore no circuit exists for the test relay Ar. So another secondary finder chosen the busy primary researcher.



   The Ar relay opens the motor circuit on the Arl contact and closes the following circuit for the Cr relay: earth, Sgr relay (fig.



  1), contact Ar2, right winding of Cr, contact Dr7, and battery. The Cr to Crl relay connects the right low-resistance winding of Ar in parallel with its high-resistance winding, causing Csr to re-establish (fig.l), provided there is no other call existing at this moment in the same group, Relay Cr closes a Cr2 circuit for relay Br which energizes relay Dr in the following circuit: Brl, Gr6, Fr6, Dr, and battery. A blocking circuit is now closed for Cr through Cr3, Er3, and the combination contact Dr6-7.

   The Dr relay, at Dr4, connects earth to the third conductor c, causing the cut-off relay Cor (fig.l) to operate through the low-resistance left winding of Lhr which remains energized in this circuit.



  The Cor relay disconnects the Lr line relay which opens the Ltr cooked air. At the same time, Csr has neutralized itself and opens the circuits of Hsr, Bsr, thus stopping any further research.



   Relay Dr, to contacts Drl and Dr3, connects the relay

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 supervision circuit Sr through the calling line circult, and to contacts Dr7-8 connects the battery via Cr4 to conductors 1 and 2 to energize the Ar relays of the start circuits of the recorders (fig. 9), and to apply a test potential to test drivers in the data logger researchers' facilities. The Br relay is now maintained through the Sr2 contacts of the Sr. relay.



   The recorders start up relays energize the Brr starter relays which close the circuits for the PR electromagnets of the recorder researchers associated with the free recorders. In the recorder circuit shown, this cooked air comprises: the battery, the PR electromagnet, the contacts Grr4, Err3, Brr3, Crrl and earth. The test relay Crr of the first seeker which reaches the circuit of the engaged secondary seeker, excludes itself through its left high resistance winding via the contact Drrl, the normal contacts and the brush a of the unit recorder , the normal contacts and the brush of the remaining digital recorders, and earth. The PR solenoid circuit is open, and the Err circuit is closed.

   The Err relay shunts' the high resistance winding of Crr with its low resistance right winding at the Errl contact, turns on an occupancy lamp BL at the Errl-2 contact, opens another point in the PR circuit by Err3, and connects a Basic drive operating signal from the disc on the call line to contacts Err6 and Err7.

   The circuit of this signal passes through the right winding of the transformer TC, the small capacitor MFl, the contact Rr6, the winding of Pr, the contact Err6, the brush b of the recorder finder, the contact Er2 (fig. 2), the conductor b of the derivative capacitor, the circuit of the calling station, the conductor a of this capacitor, the contact Erl, the brush a of the recorder finder (fig. 9), the contact Err7, and return to the transformer winding. The circuit of the primary winding of the transformer TC is completed through conductor D, contacts Frr2, Err4-3,

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Grr4, and the winding of the magnet.



   The calling subscriber now operates his disc and marks the first digit or thousand digit of the requested subscriber.



  In this way the Sr circuit (fig. 2) is open intermittently, and this relay, on each reset, closes a pulse circuit for the Ir and Hr relays (fig. 9) through the contacts
Srl and Er5. The relay Br (fig. 2) is of the slow recovery type and during the pulses it remains energized. For each neutralization of Hr, ur. circuit is closed through Hr2 and Jr3 for the step-by-step solenoid SW1 of the first digital recorder.



  The relay Ir is energized from the first pulse, and as this relay is slowly reestablished, it remains energized for the duration of the pulses. As soon as the first digital recorder reaches the first set of terminals, the following circuit is closed for relays Er (fig..2) and Ur and Vr (fig.9): battery, contact Dr7-6 (fig.2 ), lower winding of Er. recorder finder brush c (fig.9), contact Frl, low resistance right winding of Ur, winding of Vr, subnormal arc and brush b of the first digital recorder, contact Drr6, and earth. Due to the high resistance of Er, the Vr relay does not energize in this circuit. A blocking circuit for these relays is closed through contacts Ur3 and Drr6.



   Relay Er, fig.2, disconnects the auditory operating signal from the disc, and on contact Er3, opens the blocking circuit of relay Cr, which removes the test potential from the contact engaged by brush d from the recorder researcher, which neutralizes tavelais Crr (fig. 9). However, the Err relay (fig.9) remains energized through the Ur2 contact. At the end of the first series of pulses, the relay Ir is neutralized and closes a circuit for Jr through the brush of the first digital recorder.

   The relay Jr closes a circuit for the slow-acting relay Grr, via its contact Jr6 towards the earth, this blocks through the contacts Jr5 and Err2-1, and at the contact Jr4 transfers the pulse circuit via the

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 the Ir3 contact towards the magnet SW2 of the digital secondary recorder.



   When the subscriber sends the second series of pulses, the solenoid SW2 of the secondary digital recorder responds to these pulses, and the recorder occupies a position corresponding to the marked number. At the end of the pulses, the relay Lr energizes and transfers the pulse circuit to the electromagnet SW3 of the third digital recorder through the contacts Lr4, Tr6, Or6. The third series of pulses advances this recorder, and when the last pulse is received, the Gold relay energizes and transfers the pulse circuit through the Or5 contact to the solenoid SW4 of the last digital recorder which responds to the last set of pulses.



   When energizing Jr at the end of the first series of pulses, the following circuit is also closed for the relay Kr: earth, contacts Jr6 and Grr2, left winding of Kr, contact Frr6, and the drums. The Kr relay is blocked through the Kr2, Nrl, Err2-1 contacts, independently of the Jr6 and Grr2 contacts.



  The relay Kr connects the earth to the conductor b of the fundamental circuit via the, .contact Kr4, the winding of Pr, the contact Err6, and the brush b of the recorder finder, while it connects the battery to the conductor a- of the fundamental circuit, via a resistor, the contact Kr3, and the brush a of the recorder finder.



   The connection of the battery to the driver has closed a circuit for the common start relay Acr (fig. 6) of the control circuit of the first group finder via contacts Cr5 (figure 2) and J2r2 (fig. 3). . A potential is also placed on the contact of the level traversed by the broom through the broom 1, particular to the primary searcher of groups engaged.



   The arrangement of the contacts of the banks of the switches of the group seekers control circuit should be described here. There are 51 stitches or positions (the first being used AS a home position) and five rows or levels of con-

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 baked to the remaining offices, a group of twenty-five for local calls, and a group of ten to a group of researchers for special services., The contacts in level j are grouped and are used to center the brooms.



   We now summarize the operations of the system. When the Acr starter relay (fig.6) is energized, a circuit is closed through contacts Fcr2 and Bcrl for the PC motor electromagnet, and the control seeker switch turns. A circuit is also closed for the Ecr relay which keeps the earth away from the left windings of the test relay Ar (fig. 2) of all the secondary researchers connected to the primary researchers of the groups served by the control circuit. control in order to prevent some of those secondary finders from entering a primary finder while the control circuit is in use.

   When the calling trunk circuit is reached, the Bor test relay operates through the battery on the test contact. The PC motor electromagnet is disconnected, and the following circuit is closed for relays Fcr (fig.6) and Jir (fig.3); battery, windings of '-Par and Jir, level h contact and brush, contacts Bcr2 and For2, sub-normal contact N, and earth. The Fcr relay operates slowly. The Fcr and Jir relays are blocked to earth at the Brl contact (fig. 2), via the Jir3 and J2rl contacts, and the conductor c. At contact Jlrl it connects conductor b of the fundamental circuit to relay Der of the control circuit.

   The relay Pr in the recorder (fig. 9) is now energized in series with the relay Dcr (fig. 6). The Pr relay closes in Pr2 a circuit via Mr4 for the Rr relay which is blocked to earth through Rr4 and the brush c of the first digital recorder, and the contact Err2-1, provided that the switch is in one of the positions 1 to 9. This blocking circuit is not closed if the switch is in its ten position. Relay Rr closes a circuit for relay Nr. And at contact Rr5, connects Pr in a metallic hole through conductors a and b of the basic circuit.

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 mental. The Bcr relay (fig.6) is neutralized and cannot function in series with Dcr.

   The Nr relay, in Nrl, opens the Kr blocking circuit. In the control circuit, the Der relay closes the following circuit for the PC of the switch to seek control: earth, sub-normal contact N, contacts Fcrl, Dcrl, Gcr3 , PC winding, and battery. The control switch advances hand holding its' brushes through the remainder of the ten calling trunk line positions, and in its subsequent advance, each time the brush g passes through a grounded group contact, the relay Pr recorder is bypassed for now.



  Each time Pr is restored, a circuit is closed through the contacts Prl and Rr4 for the gold relay which closes a circuit via the contact Qr2 and the brush f of the first digital recorder for the SWI electromagnet. It is blocked via the contact Qr1 and the brush a of this recorder, towards the grounded switch contact 1 of the electromagnet SWl, thus keeping the circuit of the electromagnet SWl closed, even if Pr opens its rest contact before SW1 is fully excited. In this way, the first digital recorder advances until it reaches position ten for which the blocking circuit of Rr is opened.

   During the next neutralization of Pr, the relay Rr is neutralized and in Rr5 opens the fundamental circuit. J, the relay Nr a is now devoid of current., But since it is / restoring 'slow, it maintains its working contact Nr2 long enough to cause the excitation of Srr via the contacts Rrl and Err2-1, Le relay Srr close the next circuit for the relays? and Qr: earth, contacts Err1-2, Nr2, Srrl, brush. ±. of the first digital recorder, left winding of Mr, winding of Qr, and drums.

   The relay Qr closes the circuit of the electromagnet SWl which advances the first recorder to its normal position while the relay closes the fundamental circuit at the contact Mr5 and is blocked through its right winding via the contacts Frrr6, Mr3 and Pr2. If the first digital recorder is active

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 born by the impulses due to the operation of the disc, at its ten position, the relay Rr is neutralized during the first neutralization of Pr, and operation takes place as described above.



   During the opening of the fundamental circuit to the recorder, before the re-establishment of Rr and the operation of the Mr relay, the Dcr relay (fig. 6), in the searcher control circuit, is neutralized and closes a circuit for Ger, which passes from earth to subnormal contacts N via Fcrl, Dcr2, and Gcr1.



  The relay (- ', or locks up through Gcr1-2 and connects the earth via Gcr5-4, the high resistance right winding of the test relay Hcr, the brush f and the engaging terminal, to all the terminals d of the junction circuit group corresponding to the first digit marked on the disc by the subscriber. The motor electromagnet PJ of the group finder is also earthed through Gcr5, Hcrl, and Jlr4, and the group finder turns. As its brushes a and d are connected together through Jlr6, when a free connection circuit in the requested group is reached, the group finder and the associated control circuit are free, and the Hcr relay in the control switch is energized through the battery connected to conductor c through 2Ecrl (fig. 7).



   The Hcr relay connects a low real- tance test relay Scr and its own low resistance left winding, in parallel with its high resistance right winding, making the chosen connection circuit busy for other calls. - if. The Scr relay closes a circuit through Sari and Jlr5 for the group finder relay J2r which locks at the work contact Brl connected to the earth of the relay Br (fig.2) in the line finder circuit. The J2r relay completes in J2r3 and J2r4 the connection of the line finder circuit to the chosen connection circuit, and it opens in J2rl the Jlr blocking cireuit which is neutralized, thus disconnecting the group finder from the circuit. control.

   The Fcr relay is also devoid of current

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 when J2r energizes, which opens the blocking circuit of Gcr and closes a reset circuit for the control switch through contact N and contacts Fcr2 and Bcr1, If relay Aor is energized due to the fact that another connection circuit is in a call condition, the switch continues to turn and the second connection circuit is immediately connected.



   Now considering the recorder again, when the * is energized after recording the second digit or hundreds digit, another circuit is closed for Kr which extends to. through the battery, the left winding of Kr, the Lr6 contact, the Hundreds digital recorder brush b, the Mrl, Nrl, Err2-1 contacts, and earth. The relay Kr reconnects the battery to the conductor a and energizes the starting relay 2Acr (fig. 7) of the control circuit of the secondary group finder, and reconnects the earth through Pr to the conductor b. It is therefore possible that if a second group finder is taken in use until the hundreds digit has been fully recorded, the control circuit is not connected until the recorder is ready to receive the reversible pulses.

   On the other hand, if the recorder is ready to receive the reversible pulses before a second group finder has been chosen or before a control circuit is connected to a selected secondary group finder, the relay Kr gets excited again, as soon as Mr neutralizes when the basic circuit is opened to the primary group finder engaging a free junction line with the help of its control circuit, and will therefore cause the connection of a control circuit of a secondary group finder at the best possible time.



   A secondary group finder is shown in fig. 4, and its control switch in fig. 7, but since its control circuit is similar to that shown in fig. 6 it is only necessary to briefly describe the operations in the second selected step

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 tive of the group. The 2Acr starter relay closes a circuit for the 2PC electromagnet which advances the brushes to the calling connection circuit on which 2PC is neutralized, and the 2Jlr relay energizes in series with the 2Fcr relay of the control circuit. . The 2Jlr relay connects to the control circuit.

   Relay Pr now energizes in series with 2Dcr of the control circuit through conductor b of the basic circuit, the control switch still turns, and reversible pulses are fed back to the recorder circuit to count down the recorder switch hundreds. . The fundamental circuit is momentarily open to the recording circuit, the 2Dcr relay neutralizing and the 2Gor relay energizing. This connects the 2Hcr test relay and closes a circuit for the group finder 2PJ solenoid. This searches in the marked group, and when a free connection circuit is found, the 2Hcr, 2Scr and 2J2r relays are energized, completing the connection to the final finder. The 2J2r relay opens the 2Jlr cooked air which disconnects the control circuit.

   The 2Fcr relay turns neutral reads and closes a circuit for 2PC which returns the control switch to the normal position or to another connection circuit. The fundamental circuit is open, and the relays Pr and Mr neutralize each other.



   Provided that the fourth register switch, or register switch of units, has left its first position, i.e. provided at least one unit pulse has been received by the register, a circuit is still set for the Kr relay, which includes the battery, the left winding of Kr, the b brushes of the units and tens recorders, contacts Mrl and Err2-1, and ground. Relay Kr is blocked, reconnecting - the battery to the co-driver a of the fundamental circuit and the earth to the conductor b through Pr.

   The 3Acr starter relay (fig. 8) of the end finder control circuit is energized through conductor a, of the basic circuit, which moves the battery away from the common conductor, to make all the connection circuits occupied.

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 as long as the common circuit is in use.



   The arrangement of the contacts of the be, ncs of the switches of the final control circuit should be described here. These switches have a capacity of 102 points arranged in two semicircular arcs of 51 points each. Researchers have six sets of ba, lais. The normal contact N closes whenever the switch leaves its rest position, and it is only opened when the brushes have gone through a complete revolution, i.e. 3600 The lines in the upper and lower levels lower of P and.: ±. are numbered as indicated. The extreme positions H and H1 in each level are placed as shown.



   The two P levels are used retort described below for connections to P.B.X. (annex private offices). These two levels are traversed by two single-ended connected rods, separated from each other by 1800, one broom traversing the 51 upper terminals during the first half-revolution, while the other broom traversing the 51 lower terminals during the second half-revolution. The terminals for the H and H1 positions are dead pads.



   The two levels f are linked to the marker contacts d of the final researchers and are arranged in the same way as the levels P.



   Level g comprises five large segments occupying positions 8-9,18-20,29-30, 39-40 and 49-50, respectively. These segments are traversed twice by a double ended brush during each complete revolution, and grounding for the fundamental circuit takes place through these segments. The segment immediately preceding the H and H1 positions is longer than the others since the brushes have to travel an additional step through these contacts to reach the beginning of the next group.



   Levels h and 1 each contain ten terminals occupying positions 1-10 in the first half-revolution. These levels

 <Desc / Clms Page number 21>

 are connected. to the circuits of the final researcher, and there is therefore a capacity of ten final researchers in each group. However, this number may vary depending on traffic requirements. These levels are connected by two brushes and are traversed only once during a complete revolution (360)
Level j consists of a series of terminals connected to the earth and traversed by a brush with double ends. These terminals are used to center the control finder brushes.



   As the control finder can grab an end finder between positions 1 to 10, it is necessary that the segment in positions 8 and 9 of level g be isolated until the broom begins its second half-revolution. Reversible counting is therefore started on the segment in positions 19-20, and the contacts in levels p and f are numbered by tuning. The first engagement of this segment by brush g causes the 3Fcr relay to be energized (fig.8), which connects the first segment to earth (positions 8-9) during the remainder of the selective operation.



   Summarizing the operations of the circuits, the relay 3Acr (fig. 8) closes a circuit for the motor electromagnet 3PC through the contacts 3Acrl, 2Dcr3,3Fcr3 and 3Bcrl, The brushes rotate, and when the terminals of the connection circuit calling are reached, the relay 3Bcr is energized through the brush 1 and the conductor has fundamental circuit. This relay opens the 3PC circuit and completes the following circuit: earth, sub-normal contacts N, contacts 3Dcr3, 2Fcr3,3Bcr2. brush h, windings of Flr and F3r in parallel, contact 3Fcr8, and battery. The marginal relay F3r does not activate, but the relay Flr is energized and blocked through Flr3 F3r6, F2rl, the conductor and the earth at contact 2J2rl (fig.4).



  It closes a circuit through Flrl and the c onductor b of the basic circuit for the relay Pr of the recording circuit, and for the relay 3Dcr of the control circuit. The 3Dcr relay closes the 3PC circuit through 3Gcrl and 3Dor2 ,, When the brush g engages the

 <Desc / Clms Page number 22>

 first group contact connected to earth in positions 18-20, a circuit is closed through 3Gcr7,3Dcrl, 3Fcrl for the 3Fcr relay which blocks through 3Fcr? -8 in series with Flr (fig.5).



  It also connects brush g to conductor b of the fundamental circuit via 3Gcr7,3Dcrl, 3F3r2, and sets to. earth the first reversible group contact, as well as the centering contacts in: level j, via contacts 3Ecr6 and 3Ecr2. As can be seen from the previous description, this group contact occupies positions in the arc assigned to the calling junction circuits, and the sending of reversible pulses cannot begin as long as the control switch n 'has not passed beyond this group so that the first reversible pulse is always sent back from the same arc position of the control switch, regardless of whether the first or last final selector is chosen.

   The control switch continues to rotate, and for every ten steps a reversible pulse is sent through conductor b to count down the tens register in a manner similar to that originally described with reference to the thousand register,
In the recorder circuit, when the tens recorder reaches position ten, during the next re-establishment of Pr, the relay Er is neutralized and opens the fundamental circuit.



  Relay Rr opens the circuit of Nr, and between the reestablishment of these two relays, Srr is energized and closes the following circuit: battery, relay Qr, brushes d from registers of diza.ines, hundreds and thousand , contacts Srrl, Nr2, Ecrr2-1, and earth. Relay Qr advances the tens switch to its normal position.



  The Kr relay is immediately energized at. through its right winding, via the b brushes of the tens and unit recorders, and the contacts Mrl, Nrl, Err2-1. The basic circuit conductor b is closed for the start of the selection of the units. The relay Pr now closes the circuit of Rr which was blocked through the brushes c of the recorders energizing Nr again, causing the reestablishment of Srr and Qr.

 <Desc / Clms Page number 23>

 



   When the basic circuit is open to the recorder circuit, the 3Dcr relay is neutralized, opens the 3PC circuit in
 EMI23.1
 3Dcr2, and closes wine circuit through 3Dcr3,3For4, and 3Gcr3 for the 3Gcr relay. This one blocks through 3Gcr3-4.3Eor3, and 3For6; close U1 circuit through 39cr6 3Ear3,3Gcr3-4, and Xer6 for the Icr relay, prepare a circuit for the 3Hcr test relay at the 3Gcr5 contact; and closes a circuit through 3Gor6, 3Her4i, Lor3 and Flr6, for the motor electromagnet PF of the end finder. The control switch stops at the last set of terminals of the previous group of ten lines for the reason that when unit selection takes place, the switch always steps one step.



  The contacts in level f of the control switch are connected to contacts d in the end finder banks, and when the end finder reaches the terminal marked d, the following circuit is completed for the 3Hcr relay: battery, 3Hcr, contact 3Ger5, brush f of the control switch, terminal d and balance of the end finder, contact Flr5, and earth. The 3Hcr relay opens the PF circuit.
 EMI23.2
 



  When the concluding b of the fundamental circuit is closed to the recording circuit, the Dcr relay energizes again and closes a circuit for the Ycx relay: battery, winding of Ycr, contacts Ycrl, 3Gcr2, and 3Dcr2, contact under- normal N, and earth.
 EMI23.3
 



  The Ycr sP relay blocks through the yari-2, 3Eer3, and 3Fcr6 contacts. Provided that the 3HOr test relay is energized at this time, a circuit is complete for Dsr through 3Hor2, Yor5 and Msri. The Lcr relay earths the conductor b of the fundamental circuit at Lcr1, and closes a circuit for 1 motor electromagnet 3Pc of the controller.
 EMI23.4
 control mutator through Ifcr9iHcx 93Gcr The 3PC electromagnet moves the switch brushes forward. When the broom, on level f, leaves it. terminal on which it is stopped, the relay
 EMI23.5
 3Hcr is neutralized and opens the circuit of Lor which moves the earth away from the conductor b of the fundamental circuit and closes the LF circuit of the final seeker who advances to its neighboring position for which

 <Desc / Clms Page number 24>

 the 3Hcr and Lcr relays are still energized.

   In this way, reversible pulses for unit selection are fed back from the final control circuit to the recorder circuit, with the final finder taking one step for each pulse.



   In the recorder circuit, the reversible pulses are repeated by the relay Qr towards the solenoid SW4 of the unit recorder. For the. position ten of this recorder, relay Rr is released. The Srr relay is energized, and before Nr has had time to neutralize itself, a circuit is closed for Drr through Vrl, the brushes c of all the recording switches, and the contacts Srrl, Nr2, and Err2-1. Relay Drr is blocked through contact Drr5, and in Drr6 opens the circuit of relays Ur (fig.9) and Er (fig.2). The UR relay opens the Err blocking circuit (fig. 9) which in turn unlocks the energized relays in the recording circuit, except Drr.

   This also closes a circuit for the Qr relay through Drr3, the brushes e of all recorders, and the switch contacts of the solenoid SW4. Relay Qr closes a circuit to actuate the unit recorder to sa. normal position.



  The relay @ is neutralized as soon as the unit recorder leaves position ten, but in the normal position it is still energized through, towards' Drr3, the brushes of the recorders, and the Drr5 contact. A test is made to verify if all recorder switches are at their normal positions, and a circuit is closed through Qr2, all f brushes, and Drr2, to short relay Drr. An office supervisor, by operating the RK key, can close a circuit for the Drr relay and re-establish the recording circuit. The lamps A, B, C are connected to the subnormal arcs d of the first three recorders.



   Returning now to the final control circuit, when the fundamental circuit was finally open to the logger circuit, the 3Dcr relay is neutralized, and the following circuit is closed for the Mer relay: battery, Mcr relay, Ycr4 contacts,

 <Desc / Clms Page number 25>

   3Fcr4, 3Dcr3, subnormal N contacts, and earth. The Mcr relay is blocked through Mcr24, 3Ecr3, 3Fcr6, disconnects Le% 'in Morl before it has time to operate again, and on contact Mor5 closes a circuit for Xor through Pcrl, and Hcrl, The Xor relay is blocked at, tra, towards Xcr4,3Ecr3,3Fcr6, and opens on contact Xor6 the circuit of Icr which begins to be neutralized. When the Icr1 contact is closed, the Yor winding is short-circuited through the Mcr5 contact.

   The Ycr relay is neutralized. With the Ycr relay neutralized and the Xcr relay energized, an earth is connected to the lower winding of F2r, via the sub-normal contacts N, the contacts 3Dcr3,3Fcr4, Ycr3, Xcr3, Flr4. A full battery is connected to the Flr and F3r relay windings in parallel, via Ycr6, Xcr5. This battery short-circuits the 3Fcr relay which is neutralized. Relay F3r is energized and blocked through its lower winding, contact F4rl and conductor c.



   If the requested line is free, the F2r relay is energized in series with the breaking relay of this line and is blocked through its upper winding to the earth at the conductor c. The arrangement is such that the time necessary for the operation of relay F3r and for the reestablishment of Flr is sufficient to allow. be on relay F2r to operate for a free line. Ringing current is now supplied to the called line from the desired source through the winding of F4r, contacts F3r2, F2r5, called line, contacts F2r4, F3r5, and earth. The auditory ringing signal is sent over the calling line through the MFR capacitor. When the called subscriber answers, F4r gets excited and unblocks F3r.

   The called subscriber is now connected through the circuit of the line finder Fig. 2, and the relay Slr energizes through the circuit of the called subscriber, closing a circuit for the relay Fr to the, soil contacts Brlo Le Relay Fr locks to this earth via contact Gr7, independently of relay Slr and transfers the circuit from Dr to contact Sr2 of relay Sr via contacts Fr6-3. The subscribers, calling and called, are supplied with

 <Desc / Clms Page number 26>

 conversation current respectively through the relays Sr and
Slr.



   If the called line is busy, F2r is not energized, and following the operation of the F3r relay, an auditory busy signal, coming from the LV source, is transmitted to the calling line via the F3r3 contacts. , F2r6 and the MFR capacitor.



   When the F2r or F3r relay energizes, the Flr blocking circuit is open in F2rl or F3r6, and this relay de-energizes, disconnecting the control circuit. Restoring 3Fcr neutralizes relays 3Gcr, 3Hcr, Xcr and Mer, and a reset circuit for the Pc electromagnet is closed through normal contacts N and, contacts Dcr3, Fcr3 and Bcrl.



   If the called subscriber hangs up but not the calling subscriber, the relay Slr is neutralized and a circuit Blr, Slr2, Fr3 is closed for the lamp GL through, through an alarm conductor.



   When the calling subscriber hangs up, the Sr relay will neutralize and open the circuits of the Dr and Br relays. The Br relay is slowly neutralized. The counting battery is connected to the conductor via contacts Fl2, Gr5 and Dr4, to activate the SM counter fig.l. When the Br relay is neutralized, the Fr relay leaves its armatures and disconnects the battery from the meter. The relay Br moves the earth away from the conductor c. causing the re-establishment in turn of the switching relays J2r, 2J24, and F2r to the group and end searchers. These switches remain on the terminals of the trunk lines or circuits with which they were connected. Breaking the conductor c makes the circuit immediately ready for a second connection.



   Research - for an annexed office: The P level of the final control researcher is used for PBX research, and the working contacts Cor2, fige.1 and 5, cut relays for all lines in the PBX group, except the last, are connected to the terminals of this level. When the. selection of the units is complete and the Mcr relay energizes, a circuit is pre-

 <Desc / Clms Page number 27>

 pared through contacts Mcr2, Xcr1 for relay Par. The latter operates faster than the Xcr relay, and if the number requested concerns a P.BoXo group, the Par relay is energized, disconnecting Xcr at the Pcr1 contact.

   A circuit is closed at Pcr2 for the 3PC motor electromagnet which advances the control switch one step to the next set of contacts where the 3Hcr relay is neutralized, and closes the circuit to advance the end finder. to the next line of the PBX group where the 3Hcr relay is still energized. If this line is also busy, the Par relay is still energized and the control switch advances a new step, This maneuver continues until that a free line in the group is found, or until the last line of the group is reached. stopped.

   The last line is tested in exactly the same way as a single line, and if it is busy an auditory busy signal is sent to the calling subscriber.



   Special Service Calls: As previously established, the recording circuit is arranged to serve special service calls, which are designated by two digits. For these calls the numbers 01,02, etc ... are reserved. If the first digit marked on the disk is the digit "O", the thousand recorder is brought to position ten, and before the reestablishment of relay Ir, a circuit is closed through contact Grrl, brush b, and the contact Drr6, for the relay Tr which locks up through the contacts Tr5, Err2-1, and the earth. The tens recorder cannot be actuated by a third digit since its circuit is open to contact Tr6.

   Respectively, at the end of the first and the second digit, the Jr and Lr relays are energized as for a normal call. The recorder circuit now controls the selection at the two steps of group seekers At the end of the second selection, the relay Dr is energized instead of Mr through: earth, contacts Err1-2, Nr2, and Sr1, sweeps 0

 <Desc / Clms Page number 28>

 Hundreds and Thousand Logging Switches, Tr4 Contact, Dr Relay, and Battery. The energization of the relay Dr brings about the reestablishment of the recording circuit as was previously described.



   The call is routed through a regular group finder, such as the one shown in fig. 3 (full line connections), and a special service group secondary finder, to a local connection circuit terminating at a position d operator as shown in fig.ll. The said secondary researcher of groups for special services is identical to that shown in fig. 3, the connections marked X being removed and those indicated in dotted lines being established. This finder differs from an ordinary finder in that a fifth brush is provided, but its operation is practically the same. When the connection circuit is chosen, relay 1Ar (fig.ll) is energized through conductor c and call lamp CL lights up.

   The attendant inserts her plug into the jaok, which closes a circuit: relay 1Br (fig.ll), brush e of the secondary searcher for groups for special services and of the primary searcher for groups, relay Er and Gr, and connection of the line finder (fig. 2). Relay 1Br (fig.ll) neutralizes the Ar and turns off the CL lamp. Relay Gr (fig. 2) opens at contact Gr7 the circuit of Dr which disconnects the bridge for the current on the calling side. The Er relay disconnects the bridge for the current on the called side. The calling subscriber is now connected to the operator position through a metal circuit containing the Grl, Gr2 contacts.

   Power for conversation and other purposes is supplied directly from the operator's cord circuit. The Sr and Or relays are neutralized, while the Gr relay at contact Gr4 maintains the cutting relay of the calling line and at contacts Gr6-7 maintains the Br relay energized independently of the calling subscriber, for transfer. check the recovery with the operator. If this re-establishes the connection before the calling subscriber, the relay Gr switches to

 <Desc / Clms Page number 29>

 tralise and Dr's circuit is still closed, while the current bridge is connected to the calling line. The relay sr is therefore energized and closes the primitive circuit for the relay Br which maintains the. connection. The Ar relay of the junction circuit (fig.



  It) is still excited, and the CL light turns on to re-call op rarices.



   Long distance connections. Junction lines for the trunk switchboard are associated with the recording circuits through groups of relays as shown in fig. 12. The same recording circuits and the same group and end hunters as for the local calls are used.

   When the long distance operator inserts an LP plug into the LJ jack of a trunk line ending in a group finder at the automatic office, relay 2Ar (fig. 12) is energized through the conductor of the plug body, relay 2Cr is connected to conductors a and b of the junction line at contacts 2Ar1, 2Ar3; the conductor c of the junction line is connected to earth at 2Ar2; the common start stop relay for searchers of recorders (fig.



  9) gets excited and marks the calling junction line in the recorder searchers' ba.ncs through contact 2Ar4. Relay 2Cr closes a circuit for relay 2Hr which locks at contact 2Ar2. A free recorder is connected and an auditory disk maneuver signal is sent over the line in the usual way., Whereupon the trunk operator lowers the DL disk maneuver DK key, sending pulses which are received. by relay 2Cr and retransmitted to the recording circuit.



    After the first impulse is received, the following circuit is closed: battery, contact 2Ar4, relay 2Er (fig.12), sweep of the recorder finder $ (fig. 9), relay Ur and Vr, sweep b of the mile recorder in position one, contact Drr6, and earth. The 2Er relay (fig. 12) is energized and connects the 2Fr relay in parallel with 2Ar, The 2Fr relay is blocked at the conductor of the body of the plug, closes a circuit in parallel through its winding of

 <Desc / Clms Page number 30>

 right for 2Ar; connect the earth to the condactor c; and maintains the 2Hr relay at the 2Fr3 contact.

   The resistance of relay 2Er is. low enough to allow the marginal relay Vr (fig. 9) to energize, indicating to the recording circuit that the call is coming from a long distance operator. This indication at the. form of reclosing of the fundamental circuit after selection of the units.



  When the unit recorder reaches position ten, the Rr relay is released in the usual way, the Srr relay is energized, and the Nr relay is released. With the relay Vr energized, Wr is energized in place of Dr through the contacts Err1-2, Nr2, Sr1, the brushes. ±. of all recorders, and contacts Vr2 and iYr1-2. The relay Wr is blocked through its contacts Wr2 and closes the fundamental circuit through Wr4. When relay Nr de-energizes, Drr actuates the units recorder to the normal position, re-establishing all recorder circuits, as was originally described.

   At the control circuit of the final seeker, this closing of the background circuit causes a new operation of the 3Dcr reaction (fig. 8), and this relay connects the earth immediately to the winding of F2r through 3Dar2, Xcr2- 3, Flr4, before the slow recovery lcr relays override and bypasses Ycr to connect the battery and. excite F3r. So for a long distance call, the F2r relay of the end finder is connected before the F3r relay:

     If the requested line is free, F2r is energized and immediately opens the circuit of Flr which disconnects the final finder from the control circuit, It is clear that in this case, F3r cannot be energized since its circuit is open in Flr3, and the connection to the called line is made without ringing current being applied from the end finder. If the requested line is busy, relay F2r cannot be energized, F3r is energized when Icr is reestablished in the control circuit; and an auditory busy signal is sent. The control circuit is disconnected in the usual manner.

 <Desc / Clms Page number 31>

 



   Lowering a BK key (fig.12) to the inter-urban panel turns on the occupancy lamp BL of all the circuits occupied at this time.



   Providing a long distance connection and testing a circuit monitor. As previously explained for the provision of a trunk connection and for an air-room supervisor testing, a special set of switches can be taken into use so that any subscriber line, even busy. , can be reached by the long distance operator or the said supervisor. For each group of one hundred lines a special end finder is provided which differs from a regular end finder in that it is arranged to stop on the requested line without trying or ringing.

   This final finder, whose circuits are shown in fig. 14, is associated with the same control circuit as the regular final researchers.



   A group of special relays, Fig.13, are connected to the jacks, shown on the TB trunk board, and on the supervisor's WCD test board, which is similar to the trunk line circuit shown in Fig.12. This group connects to a regular recorder circuit and provokes. the operation of the marginal relay Vr to indicate a long distance call. Relay 2Ar (fig.13) closes circuits for the occupancy lamps BL to both panels.



   The call is extended under the control of a recording circuit through group finders, primary and secondary in the ordinary way, to a special end finder (fig. 14).



  When a special end finder is equipped in the group of end finders, served by the control circuit, the dotted line connections, shown in figo8 extending to the contacts lFlr6 (fig. 14), are inserted into the relay circuit. Per, and the X option is moved away to prevent automatic search when the control seeker is brought to the start of a PBX group,

 <Desc / Clms Page number 32>

 being associated with m special end finder When the control finder seizes the engaged end finder, the lFlr and 1 lF2r relays are energized in parallel with the control circuit, but the lFlr relay alone cipers and locks to the conductor c.

   The end finder is controlled in the usual way for the selection of tens and moths by the control circuit, and on completion of the selection of units when re-closing the basic circuit, the entire battery is connected to the windings. lFlr and lF2r relays. The lFr2 relay now energizes, locks to the conductor c through its upper winding, neutralizes the LFr relay which disconnects the control circuit, and prolongs the connection to the called line without the application of the ringing current. and regardless of the condition of that row. The supervisor is provided with an OTK key to connect to the earth a circuit passing through the brushes of the group searchers, primary and secondary, and the brush c of the final searcher, in order to make the called line busy.

   The circuit through the end finder brush c can only be closed in this way.



   False calls; When a recording circuit is connected during the excitation of Err (fig. 9), the following circuit is completed for the motor electromagnet TA of the fixed time switch R: earth, Erl-2 contacts, Nrl, KRl, winding of the electromagnet TA, and battery. when the first digit is received, this cooked air is opened in Krl by the operation of the relay kr, but if no pulse is received before a predetermined interval, for example 30 seconds, has elapsed. time switch T advances its brush 2 on contact 4 and closes the following circuit: battery, relay Hr and Ir, contact Jr7, arc 4 and brush 2 of switch T, contact Jrl, switch spring I of the electromagnet SWl, and earth.

   The Ir and Hr relays now energize, and Hr closes a circuit for the solenoid SW1 which opens the circuit of Hr through its switch contacts. The relay Hr and the electro-magnet SW1 react until the thousand recorder

 <Desc / Clms Page number 33>

 reaches its position ten, for which the Jr relay energizes and blocks. The Tr relay is energized to trace the Grrl contact, the brush 1 of the first recorder the Drr6 contact, then locks to the Err2-1 contacts. The TA electromagnet is blocked through the following circuit: battery, TA, arc 3, brush 1, contacts Tr1-2,
Lr7, Jr6, and earth.

   The circuit of relays Hr and Ir is transferred through contact Tr7, and the secondary recorder is brought to position ten for which relay Lr is energized and opens the pulse circuit to the electromagnets of the recorders. The Hr and Ir relays are kept energized. Relay
Lr opens the TA circuit to contact Lr7. At the same time, the relay Kr is energized through contacts Gr2 and Jr6. The selection is made as if the digits 00 had been marked on the disk and is carried out as for a special service call.



   Case where all the connection circuits are occupied: It must be remembered that the Mr relay in the recorder circuit is energized and blocked through the working contact of the Pr relay when a group finder starts his search for a circuit. fired of free connection in a requested group, and is blocked when the relay Pr is neutralized during the opening of the fundamental circuit when a free connection circuit is found. The Nr and Rr relays are neutralized during the search. The Mr. relay in Mr1, keeps the circuit of the Kr relay open. So as long as the research continues, the relays Kr and Nr are neutralized, and in this condition a circuit is closed through the contacts Kr1, Nr1, Err2-1, for the motor electromagnet TA of the switch T.

   If after a predetermined time interval, for example ten seconds, a free connection circuit has not been found and the Mr relay is neutralized while Kr is energized when the brush 2 of the switch T is on the contact 5, a circuit is closed for Fr1.

   This circuit is extended through contacts Mr2, Jrl-2, Lr1, to the electrical switch contacts.

 <Desc / Clms Page number 34>

 tro-magnet SW2 If the Lr relay is energized, it extends this circuit through the Lr1-2 and Or 1 contacts to the switch contacts of SW3, and if the Or rela.is is energized, it extends it through Or2 to the switch contacts of SW4. The relay Frr is blocked to earth at the Erl-2 contacts, connecting the auditory occupancy signal through conductor B to the Frr5 contacts towards the transformer TC in place of the auditory disc maneuver signal.

   Opening the contact Frrl introduces the high resistance winding of Ur in the circuit of this relay (fig. 9) and of the relay Er (fig. 2). The relay Er is deactivated, and an auditory busy signal is sent to the calling subscriber through the circuit originally described with reference to the transmission of the auditory signal to operate the disc. When the subscriber replaces his receiver, the switches are released. If, after the expiration of the determined time interval, the recorder is not released when the brush 2 of T engages the contact 6, an alarm lamp GL lights up.



   Incomplete calls: The circuit for the TA electromagnet of the time switch, described in the last paragraph, will be completed each time the connection is established and until the digits are registered, but immediately the first digit - fre is registered, the Kr relay energizes and opens the TA circuit.

   So if the calling subscriber delays the operation of the disc after any digit, the alarm lamp GL lights up through the alarm driver and the brush 2, after a determined time. premature restores: If the calling subscriber abandons the call prematurely, before disc drive pulses have been sent, but after a recorder circuit has been selected, the reestablishment of the Sr relay (fig.2) causes the operation of the Hr relay (fig.9) which moves the recorder one thousand steps forward. The Br, Dr, Gr relays, fig. 2 are also released, and the Crr relay (fig. 9) is neutralized.

   For Position one of the mile recorder, the ordinary circuit is

 <Desc / Clms Page number 35>

 completed for the Ur (fig. 9) and Er (fig. 2) relays, but this circuit is opened by re-establishing Dr (fig. 2). The Err relay (fig. 9) is therefore released and the Ir and Hr relays are neutralized.



   In position one of the thousand recorder, the Jr, Grr relays are energized, and a circuit is closed for the Drr relay, via the Grr3 and Ur1 contacts. Relay Drr is blocked and the recorder circuit is brought back to rest. well known way,
If the calling subscriber restores the connection prematurely after part of the disc operation, the SrBrDr relays (fig. 2) are neutralized, the circuit of the Fr (fig. 2) and Ur (fig. 9) relays is open, the Err relay (fig.9) is released, and during the reestablishment of the slow-acting relay Grr the above-described circuit is closed to re-establish the Drr relay.



   Called receipts from remote offices; Two-conductor trunk lines coming from remote offices terminate in relay groups such as those shown in fig. 15, which are attached to seekers in arrival groups similar to seekers.

   shown in fig. 4. As has been previously described, when at the end of the first selection the conductor a is connected to the battery in the recorder circuit through the contact Kr3 and the conductor b, and to the earth through the contact Kr4, the winding of Pr. and the contacts of Erra, the high resistance supervision relay Sbr, which is normally connected through the junction line in series with the low resistance supervision relay Sar to the relay groups of fig. 15, gets excited.



  The Sar relay remains neutralized. The Sbr relay closes a circuit through Crl, and closes a circuit for Br through Ar7. It opens the branch circuit through the Sbr relay and completes a metallic connection through the a and b conductors, the Arl-2 and Ar4 contacts, and the incoming group finder. The Br relay is blocked to earth through the third conductor. the gold relay is now in series with conductor a and is shunted by resistor R and one of the conversation capacitors.

   This Cr relay is

 <Desc / Clms Page number 36>

 polarizes and cannot be energized at this moment nor during the establishment of the connection which takes place in the ordinary way under the control of the recording circuit. ,
At the end of a selection, or during a premature recovery, when Drr (fig. 9) is energized in the recording circuit to bring about the recovery of this circuit, a potential of opposite polarity is connected to the conductor. a for a short time interval through Grr5 and Drr4, while the slow acting relay Grr is reestablished. The Cr relay, which always finds an earth through the Acr relay of the control circuit of a secondary group finder or a final finder, is now energized and unlocks the Ar relay which cannot energize again for the. slow recovery period of Br.

   The high resistance derivative relay Sbr energizes through battery and earth to the calling line cord circuit through Sbr (see fig. 2) and a delay and blocking relay Br on contacts Br2 and Abrl. The relay Br blocks through its high resistance, left-hand non-inductive winding, in series with its right winding to save current and make the relay relatively fast on recovery at the end of the conversation.



    When the called subscriber answers, conversation current is supplied through Scr which gets excited and bypasses Sbr causing the excitation of Sar and Slr. Relay Sar blocks Br, while Slr - operates and causes the operation described for the case of a local call. In the case of a premature recovery, neutralization of Br (fig. 2) brings about the reestablishment of the recording circuits as previously described. The relay J2r in fig. 3 of the primary group finders is slow-acting in order to allow sufficient time for the pulse of opposite polarity, mentioned previously, to be sent to the group of arrival relays and so that the Cr relay of this group is energized.

   However, when energizing this relay, no circuit is found for

 <Desc / Clms Page number 37>

 polarized and cannot be energized at this moment nor during the establishment of the connection which takes place in the ordinary way under the control of the recording circuit.



   At the end of a selection, or during a pre-mature restoration, when Drr (fig. 9) is energized in the recording circuit to bring about the restoration of this circuit, a potential of opposite polarity is connected to the conductor. a for a short time interval through Grr5 and Drr4, while the slow acting relay Grr is reestablished. The Cr relay, which always finds an earth through the Acr relay of the control circuit of a secondary group finder or a final finder, is now energized and unlocks the Ar relay which cannot energize again for the slow recovery period of Br.

   The high resistance derivative relay Sbr energizes through battery and earth to the calling line cord circuit through Sbr (see fig. 2) and a delay and blocking relay Br on contacts Br2 and Shelter. The relay Br is blocked through its non-inductive winding to na.ute resistance and to the left, in series with its right winding to save current and make the relay relatively fast when restoring at the end of the conversation.



  When the called subscriber answers, conversation current is supplied through Scr which gets excited and bypasses Sbr causing the excitation of Sar and Slr. Relay Sar blocks Br, while Slr operates and causes the operation described for the case of a local call. In the case of a premature recovery, neutralization of Br (fig. 2) brings about the reestablishment of the recording circuits as previously described. The relay J2r in fig. 3 of the primary group finders is slow-acting in order to allow sufficient time for the pulse of opposite polarity, mentioned previously, to be sent to the group of arrival relays and so that the Cr relay of this group is energized.

   However, when energizing this relay, no circuit is found for

 <Desc / Clms Page number 38>

 Sbr, and the relay Br is released, causing the resumption of successive switches.



   It can be seen that no means are provided to make the two-conductor trunk line busy when the control switch associated with the sending end finder is busy. This does not materially affect the operation of the system since the average time during which a control circuit is in use is very short. If the corresponding control circuit is used when a trunk line is chosen, only a very short time elapses before it becomes free and can extend the connection across the line. junction envisaged. An OJ jack is provided to free the junction line,
 EMI38.1
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1 - Automatic or semi-automatic telephone system, in which one moen is provided for establishing long-distance calls, and in which the conversation switches at the final stage of switching are operated under the control of circuits, common, each a series of Conversation switches but individual at the final switching step, characterized in that the same final conversation switches are used to extend ordinary calls and long distance calls, means being provided, in said common control circuits, by which different operations take place at the final conversational switches to complete the two types of connections.

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


    

Claims (1)

2 - In a telephone system of the kind in which the conversation switches at the digital switching stages are operated under the control of control circuits, each as provided with a series of conversational switches but individually at a switching stage, switches are provided to establish both ordinary and trunk connections, and common control circuits provided with <Desc / Clms Page number 39> means for exerting a distinction whereby, in the case of an ordinary call, a ringing current is automatically applied to a requested line, while in the case of an interurban call, My connection is complete to a requested line without any automatic application of ringing current. 3 - Automatic or semi-automatic telephone system, in which means are provided for establishing interurban calls, and in which the conversation switches at the digital switching stages are operated under the control of control circuits each common to a series of conversational but individual one-stage switches, characterized in that the same conversational switches are used to serve both ordinary and toll connections 4 - Automatic or semi-automatic telephone system, in which the conversation selector switches at the digital conversation stages are actuated under the control of control circuits each common to a series of conversation switches, but individual to a communication stage. switching, characterized in that special conversation switches are provided to set up preference calls, for example calls from a long distance operator position or from the table of a circuit supervisor, these so-called switches Conversation specials being adapted to operate under the control of control circuits which can direct the operation of conversation switches used to extend ordinary calls. 5 - Telephone system, as claimed in 1 or 2, in which means is provided in said control circuit for distinguishing between the different types of connection to be made in response to a signal received through the conversation circuit. 6 - A telephone system, as claimed in any one of the preceding claims, in which the long distance and ordinary calls are established under the control of a mechanism. <Desc / Clms Page number 40> recording system which records the designation of a requested subscriber, and in which the same recording mechanisms are adapted to control the establishment of two types of calls, 7 - Telephone system, as claimed in 1, 2 and 6, in which the said recording mechanisms are accessible to the local subscriber lines and to the positions of long distance operators, and according to the path through which they are taken in. use, are adapted to exercise a distinction in the so-called common control circuits, whereby different operations take place in the said conversation switches for ordinary and long distance connections. 8- Telephone system, as claimed in 5 and 6, in which a recording mechanism controls the selective operations at the digital switching stages by means of reversible pulses transmitted by the apparatus of this mechanism through a closed circuit extending to said recording mechanism, and in which said signal consists of an opening of said closed circuit to the recording mechanism at the end of said selective operations. 9 - Telephone system, as claimed in 1 or 3, characterized in that the circuits of the final call switches and their associated common control circuits are arranged so that for ordinary calls the requested line is ringed. automatically while for long distance calls the automatic ringing is prevented and the call can only take place by the action of a long distance operator. 10 - Telephone system, as claimed in 1, 3 or 9, in which the operation of a relay in said end conversation switches is caused in the case of ordinary calls at the same time as a circuit is completed to try the called line and is delayed in the case of long distance calls until the requested line is tried. 11 - Telephone system, as claimed in 4, in which the circuits of said special final switches of conver- <Desc / Clms Page number 41> stations are arranged so that they are able to stop on the requested line without testing the condition of these lines or without applying ringing current to them. 12 - Telephone system, as claimed in 4, in which said special conversation switches are arranged in multiples, which are separated from multiples of the switches used for ordinary connections, and in which the connection is adapted to be extended to through them selector switches of groups placed at the arrival ends of the junction lines extending from the interurban or straight position (s) 13 - telephone system, as claimed in 6,7 or 8, in which said recording mechanism is provided with a marginal relay, which, when said recording mechanism is taken in use for prolonging an ordinary call, is adapted for remain inoperative, but, when the said recording mechanism is used to extend a long distance call, operates and causes changes of circuits by which a distinction is made in order to prevent the called subscriber from being automatically rung. 14. A telephone system, as claimed in any one of the preceding claims, in which said conversation switches consist of single movement switches of the mechanical action type. 15 - Automatic or semi-automatic telephone system as described above and as shown in the accompanying drawings ABSTRACT. The invention relates to systems for central automatic or semi-automatic telephone offices, and it includes the new facts shown and described herein. More particularly, the invention includes an arrangement in which the same recording circuits and the same switches of their conversation selectors are used for long distance calls and for ordinary local calls, the switches. <Desc / Clms Page number 42> final selectors being arranged to suppress or to apply a ringing current depending on the type of call being handled. The distinction is made in the control circuits common to a series of final selectors under the influence of the recording circuit. The control circuits also control the selective operation of the final conversation selector switches. For tests by the circuit supervisor, or for provision by a toll communications operator, a special train of conversation selector switches is provided which are controlled by control circuits also associated with a series of ordinary conversation switches. The special final selector switches are arranged to stop on the requested lines without testing or ringing.