CH137598A - Automatic telephone installation. - Google Patents

Description

  

  Automatic telephone installation. The present invention a. for object an automatic telephone installation in which the devices of the subscribers can be connected to devices controlled by pulses, for example, selectors or meter relays, through a line which is the first or can be the first taken into use for establishing -d'un connection, and the invention can be applied, for example particularly to small private telephone stations or offices.



       The installation according to the invention comprises a circuit for transmitting the call from a subscriber of a device controlled by current pulses to another as a result of the emission of a pulse .d 'call when the subscriber activates his dial,

   which means that the subscriber with whom a connection is desired is accessible to the second mentioned device controlled by current pulses. An embodiment of the object of the invention is shown, by way of example, in the appended -dessin, .in which: FIGS. 1 to <B> He </B> show in -diagram the circuits by which various connections can be made.

   Fig. 1 shows the line cut-off and subscriber connection relays in the local exchange; fig. <B> 9 - </B> shows the battery supply group connected to the primary line chosen first god; fig. 3 shows the battery power supply group connected to the primary line chosen second; fig. 4 shows the relay registrar connected to the first primary line;

   Fig. 5 shows the relays recorder connected to the second primary line; fig. 6 shows a recorder different from that shown in fig. 4; fig. 7 re presents the change devices: batteries, bells and busy signal;

   fig. $ shows a variant of the positive busy signal; Fig. 9 gives the general diagram of assembly at the large central office, that is to say the relationship between FIGS. 10 and 11;

    Fig. 10 shows the repeater of the main central office which is accessed by a sub-central and which has access to the sub-central, while FIG. 11 shows a selector switch having access to the normal type selector relay group.



  To follow the assembly diagram, the figures must be arranged in the following order: fig. 1 on the far left, fig. 2 to the right of the upper part of FIG. 1, FIG. 3 to the right @of the lower part of fig. 1, FIG. 4 on the right -of fig. 2, the.

         fig. 5 below fig. 3; fig. 7 can be placed either above FIG. 2, or above FIG. 3 according to the battery supply relay group that is used: 1-a fig. 10 should be placed on the upper left side of fig. 2, while fig. 11 should be placed to the left of the fi. 10; the fia-. 6 is a variant which can replace the fi-. 4.



  Referring to the drawings, the operation of the installation will be best understood by first describing the initiation of a call, assuming both battery supply groups are unoccupied.



  Suppose that subscriber No. 11 picks up his receiver to establish communication with subscriber No. 12, that is to say that it is desired to establish a simple local call.



       It should be mentioned that the subscribers connected to the small private secondary office have a number starting with the number 1. This, to distinguish them from the subscribers connected to the main office, where. subscriber numbers always begin with a digit other than 1. Therefore, the first digit distinguishes between a call for a local subscriber and a call for a subscriber at the main office. When the subscriber no. He picks up his receiver, the following circuit becomes weak: earth, contact 21, subscriber line, contact 22, line relay MI to the battery.

   The line relay is energized and completes the following circuit: earth, normally closed contact 23 of the BLI trip relay. housed in the battery power supply group Gl, conductor 24, contact 25, contact 26, of relay LTS11, lower winding of relay OTSI1 towards the battery. At the same time, a second circuit is completed as follows:

       contact, earth 95, line 96, contact 27 normally closed. of relay RL2 of power supply group @ of battery G2, contact 28, resistor 29, contact 30, contact 31 of relay LTS11, lower winding of relay OTS1I towards the battery.

   Resistance 29 is calculated in such a way that, under .the conditions above, the relay OTSII is energized before LTS11, thus opening contact 31 and preventing the energization of relay LTS11. Consequently, the call is transmitted by the subscriber's line and by the contacts 32 and 33 of the relay OTS1I to the line relay LRO of the battery power supply group Gl. The LRO line relay, therefore, is excited,

    and complete at contact 34, a circuit for relay RLl, as follows: earth, contact 34, contact 35 of relay LS, relay RLI to the battery. As a result, the relay RL1 is energized and completes at contact 38 a circuit for the group of relays shown in FIG. 7, for a purpose which will be described later.

   Relay LR1 also closes contact 37 and opens contact 23; the opening of this contact prevents the power supply group Gl from being excited by any other subscriber; at contact 37, the RLI relay connects the earth to the in terurban tripping line 38 so as to energize the switch relay C011 by the contact 39 of the OTSiI relay. The RLI relay also provides a blocking circuit for the OTSIl relay from the earth, through contact 40, conductor 55, contact 56,

   the OTSI1 relay to the battery; this relay, therefore, remains energized outside the initial supply circuit.



  When the relay C011 is energized, it opens contacts 22 and 21, thus disconnecting the line relay LII which de-energizes and opens the circuits by which the supply groups GI and G2 had been originally tested, and the circuit Gl had been busy.

    However, other operations take place in the battery power supply group G1. The energization of the LRO and RLl relays together complete a circuit for the OS relay as follows: earth, contact 40, contact 41, normally closed contact 42, OS relay to battery. The OS relay energizes the LR1 relay and the group of conductors 43 and 44 which go to the main office at contacts 45 and 46 and connect to. its place the BBl relay by the following circuit:

   conductor 43, contact 47, contact 48, contact 49, contact 50, upper winding of relay BB1 on earth. The lower bearing of the BBI relay is connected from the battery, through contact 51 and contact 52, to the conductor 44, so that the battery line is now connected from the GI relay group to conductors 43 and 44 to energize the .de dignified relay, said relay being similar to LR1 relay in that it has no battery or earth connection and is normally linked across conductors 43 and 44,

   so that it is excited in series with the relay BBl. The subscriber then begins to actuate his calling device to send a series of pulses corresponding to the first digit fre. A single pulse is transmitted when the first digit has been marked, since the number to be marked on the dial will be number 12 and; therefore, the LRO line relay de-energizes only once.

   Relay OS closes .au contact 53 a blocking circuit for itself, independently of contact 42 and contact 41, so that it is directly controlled by contact 40 and relay RL1. When the LRO relay de-energizes, it opens contact 49, which causes the battery to stop being supplied by the BBI relay passing through conductors 42 and 44 leading to the main office, and the line relay, from that office. also de-energizes.

    The LRO relay also closes, at contact 57, a circuit for the CHI relay as follows: earth, contact 40, contact <B> 57, </B> contact 58, contact 71, contact 72, CHI relay to the battery. A branch of this circuit extends through conductor 5'9, contact 60:

  of the FRB relay, the normally closed contact 61 of the FRC relay, the winding of the FRC relay, the contacts 62, 63, 64, 65, 66 of the counter relays CRO, CR8, CR6, CR4, CR2 to the CRI relay. The relays <I> CHI, </I> FRC and CRI are all excited.

   When energized, the CHL relay completes a circuit for the ACHI relay, as follows: earth, contact 40, contact 70, ACHI relay to battery. The FRC and CRI relays are blocked, in the excited state, in the following circuit: earth, contact 40 of the RLI relay, contact 67 - of the ACH1 relay, contact 218. contact 68 of the relay <I> FRA, </I> contact 69 of the FRC relay, FRC relay, contacts 62, 63, 64, 65 and 66, CRI relay to the battery;

    the contact 61 is open, but following the closing of the circuit via the conductor 21 $ and the contact 67, this has no effect. The CHI relay at contact 7-8, prepares a circuit for its excitation independently of contacts 71, 72, (contact 72 being open when relay ACHl is energized. When the first impulse ceases, relay LRO is energized @ again, contact 49 closes, re-energizing the main office line relay @, contact 34 closes to prevent the RLI relay from de-energizing.

   This RLI relay being slow to trigger does not de-energize as a result of: the momentary opening of the circuit. When energizing the re- Telais LRO, contact 5 7 is opened, thus opening the circuit of the CHI relay which, as a result, de-energizes after a short interval. Before this happens however, thanks to the activation of the LRO relay after the first pulse, a circuit is established as follows: earth, contact 40, contact 41, contact 76, conductor 219, contact 77 of the FRC relay , in lower bearing from the FRB relay to the battery.

   The FRB relay is energized in this cir cuit, opens the contact 60 and connects the contact 270 to the conductor 59 with the FRA relay. However, since the conductor 59 is not again connected to da. earth, the excitation ii relay FRB in this case has no effect.

    When the ACHl relay de-energizes, the following circuit for the IS relay of the second battery supply group G2 is established: earth, contact 40, contact 78, contact 79, conductor 80, contact 81, conductor 82, contact 83, conductor 84, contact 85 of relay RL2 of the second battery supply group G2 and upper winding of relay IS to the battery.

   This circuit is established because the first series of pulses includes only one pulse and, consequently, the relay CR1 was energized when a movement ceased. If the series had consisted of a greater number of pulses, the relay CR1 would not have been energized and this circuit would not have been established, which will be explained below.

   The purpose of establishing this circuit is that, now that the call is known to be to a local subscriber, it is possible to use a second battery supply group which does not have , no access to the main office, and thus leave the Gl battery power supply, which has access to the main office, free for another call.

   It will be recalled that we have assumed that the battery power supply unit G2 has not yet been used. After the IS relay has been energized, the following circuit is established: earth, contact 27 normally closed, contact 86, conductor 87, relay LS of the battery supply group G1 to the battery; then the LS relay is energized, its excitation blocks it on contact 88 and establishes on contact 89, the circuit follows:

   earth at contact 34, contact 89 transfer conductor 90, contact 91 of the OTSII relay to the lower winding of the LTSIl relay and. battery. As a result, the LTS1I relay is cited in this circuit and at contacts 912 and <B> 93 </B> connects the LRL line relay in circuit with the subscriber line.

   The LS relay when energized, opens the circuit of the RLI relay at contact 35, this relay de-energizes, therefore, and, opening contact 40, allows the relays <I> OS </I> and LS to get de-excited.

   It also cuts off the earthing of the conductor 55 and allows the relay OTSll to de-energize. As a result, the OSTII relay disconnects the GI relay group allowing the relays of this group to return to the normal state, including the FRC and CRI relays.

   Due to the slow tripping of the RLI relay while this happened, the connection was transferred and the LRL relay of the battery supply group G2 is. energized on the worthy of the subscriber establishing a circuit for relay RL2 at contact 94 as follows: earth, lower winding of relay IS, contact 94, relay RL2 to battery.

   Consequently. the relay RL2 is energized and or vre the contact 27, thus opening the exciter circuit of the relay LS, which occurs in the event that the relay RLI of the battery power supply group Gl should de-energize before the relay RL2. In general, the RL2 relay will be the first to energize due to the delay of the RLI relay to de-energize,

   which means that in reality it is the opening of the blocking circuit of relay L8 on the contact <B> 88 </B> which produces the de-energization of the LS relay as mentioned previously.

   The relay IRL2, at contact 95 connects the earth to the tripping conductor @ of the trunk line 96, thus keeping the switch relay C011 energized in the following circuit after the contact 37 has been put out of earth by the tripping conductor of interurban line 38 in groupF G1: contact on earth 95, conductor 96, in upper bearing of relay LTS11, con tact 97, relay <B> 11.1 </B> to the battery.

   Immediately after the relay RL2 is energized, it completes a circuit for the BBC2 relay as follows: earth,: contact 95, contact 315, contact 11.1, relay BBC2, through resistor 113 to the battery; BBC2 is energized in this circuit and opens contacts 115, 116. 117 and <B> 118 </B> thus disconnecting the conversation conductors of the called subscriber, during the transmission of the impulses.

    The two relays LTS11 and C011 are kept energized in the blocking circuit described above, and everything is now in a state to allow the subscriber to bring the dial to the second digit, in this case. , the number 2.

   On the first impulse, when the subscriber's line is open, the LB.L relay de-energizes and establishes the following circuit: earth, contact 98 of the RL2 refilais, contact 99 of the relay BR2, contact 100, contact 101, relay <B> CH'-) </B> to the battery, tan say that a derivative circuit extends through the idle contact 102 of the SRB relay, normal contact 10.3 of the SRC relay, the SRC relay, the contacts 104, 105, 106, 107, 108 of the SR0 relays,

          SR8, SR6, SR4, SR2 and the SRI relay to the battery. The SRC and SRI relays are listed in series.

   The CH2 relay by being energized completes at: contact 110 an exciter circuit for the ACH2 relay which also energizes, and at contact 111 completes a blocking circuit for the SRC and SRI relays, as follows: earth, contact 95, contact 111, contact 112, contact 109, SRC relay, contacts 104, 105, 106, <B> 107 </B> and 108, SRI relay to the battery.

   After the end of the first pulse, when the LRL relay is energized again, the following circuit is established: earth, contact 98, contact 123, contact 124, contact 625 - of the SRC relay, lower winding of the SRB relay towards the battery. The SRB relay is energized and closes a blocking circuit for its lower rolling sound by 4th contact 123 and;

         as the series that was transmitted has two pulses, the CH2 relays <I> and </I> ACH2 remain excited. As a result, the second pulse begins and the LRL relay de-energizes again and this time a circuit is established for the SRA relays. <I> and </I> SR2, as follows:

   earth, contact 98, contact 123, contact 101, contact. 125, contact 126, SRA relay, contacts 127, 128, <B> 129, </B> 130, -from relays SR9, SR7, SR5, SR3 to relay SR2. The SRL and SRA relays are energized in this circuit and are blocked, energized in the following circuit: earth, contact 270 of relay ACH2, contact 968 of relay SRI, contact 131, relay SRA, contacts 127, 128, 129, 1.30 to relay SR2 to battery.

   At contact 13i2, a circuit is established for the upper winding of the SRB relay by the above-described circuit, comprising contacts 124, 123 and 918 to earth. The SRB relay remains energized in its upper winding in this circuit, because the SRA relay has opened the contact 112, and thus opened the blocking circuit for the SRC relay and the SRI relay, and hence,

    has opened the circuit for the lower winding of the SRB relay. The SRC and SRI relays therefore de-energize. The blocking circuit for relays SRA and SR2 is now established: from. as follows:

    earth, contact 40, contact 111, contact 213 of the SRC relay, contact 131, SRA relay, contacts <B> 127, </B> 128, 129 and 130, SR2 relay to the battery. We will see that the SR2 relay must not close its contact before the SRA relay has opened on:

  contact 112, because it is important that the relay SR3 does not energize, which could occur if the relay SRA were slow to open the contact 112. The relay SR2 is, therefore, energized and remains energized since it does not there are no other impulses to be sent to choose subscriber no.12. The relays SRI and SR2 being energized successively, the test conductors TIl and T12 of subscribers no. 11 and 12 are tested successively.

   The SRI relay a. was energized when the: test conductor has been connected to 1_a, earth through the upper winding of the LTSll relay and, consequently, the following circuit has then been established: earth, contact 95, conductor - trunk line 96, upper winding of relay LTSll, contact 97, conductor Tll, contact 134, conductor 135, contact 136 of relay ACII2, .contact <B> 137 </B> IS relay, contact 138. CH2 relay, BR2 relay to the battery.

   Consequently, relay BR2 is energized and at contact 139, connects the earth through conductor 160 to the busy signal circuit, while at contact 140, it prepares a blocking circuit for itself, circuit which is not established, however, because the closing of contact 134 is only temporary, relay SRI de-energizes at the beginning of the second pulse and relay SR2 energizes and closes contact 141.

    The closing of contact 141 by relay SR2 completes a circuit for testing the line occupancy of subscriber no 12. If this subscriber is busy at the moment, its test conductor 112 will be connected to earth and then relay BR2 will be energized by contact 141 in one. circuit similar to that described by the opening of contact 134. As there are no more pulses, relay CH2 de-energizes after a short interval.

   The ACH2 relay, which would normally de-energize after a short interval corresponding to the inertia of the CH2 relay, does not de-energize at this time because it is blocked in the energized state in the following circuit: earth, contact 95, con tact 142 of relay LS, contact 140, contact 141, ACH2 relay to the battery. The deexcitation of relay CH2 completes the blocking circuit for relay BR2 as follows:

   earth, contact 95, .contact 142, contact 140, contact 143 of relay CH2, relay BR2 to the battery. The relay BR2 connects the signa-1 of occupancy -of the driver 159 by the contact 144 -so as to signal to subscriber 11 that the number he is requesting is busy. In this case the subscriber will replace his receiver, opening the circuit for the LRL line relay, which, in turn,

   opens the relay circuit RL2 and the opening of the contact produces the de-energization of all the relays which depend on this circuit and the second battery supply group G2 as well as the second recorder return to the normal state and are available for a new call.

   Assuming, however, that subscriber 12 is not busy, relay BR2 would not be energized by the closing of contact 141 and, when relay CH2 is de-energized, the following circuit would be established: earth, contact 95, contact 145. Of relay CH2, lower winding of relay RR2, contact <B> 1.37, </B> con tact 136, conductor 55, contact 141, test conductor T12, relay C012 to the battery.

   In this: circuit, relays BR2 and <I> C012 </I> get excited, and the C012 relay disconnects the L12 relay from the called subscriber line so as to prepare a free circuit for the. alarm. The RR2 bell relay when it becomes energized, opens contact 114 which thus allows the BBC2 relay to de-energize,

          @ so as to close in its contact 148 a short-circuit for the lower winding of relay RR2. Relay RR2 at contact 564 short-circuits the lower winding of relay BB2 to the battery, this slows down the operation of relay BB2 and makes it insensitive to alternating current;

   furthermore, at contact 154, the upper winding of relay BB2 is bypassed through resistor 155, to contribute to the above effect. However, the relay BR2 does not become unoccupied again by the fact that its lower winding is short-circuited, since it is locked in the excited state by the intermediary of its upper winding in the following circuit:

       Bell battery, relay <I> RB </I> (fig. 7), conductor 157, upper winding of relay RR2, contact 149, contact 515, contact 95 to earth.

    At the same time the generator current of its nerie is led to the line of the called subscriber, by the following circuit: generator earth pole, conductor 161, contact 150, conductor 151, contact 115, which is closed. currently due to the fact that the relay BBC'2 is inert; conductor 119, contact 152, con tact B12, line, of called subscriber, no. 12, return to conductor A12, @ contact 153, conductor 121, contact 1.17, contact 154, resistor 155 to earth.

   It will be noted that this ringing circuit is not established before the BBC2 relay has been de-energized, but that it may take a short time before its exciter circuit has been opened.

   This gives ample time to the relay <B> COL) </B> -to get excited and trigger relay L12. The ringing continues until the called party answers, so that a circuit for relay BB2 is established as follows:

       earth, upper winding of relay BB2, conductor 1'56, contact 117, conductor 121, contact 153, conductor A12, subscriber line, conductor B12, contact 152, conductor 119, contact 115, conductor 151, contact 150, conductor 161, transformer winding H, matrix, contact 206 from relay MR (fig. 7) to the battery.

   The relay BB2 is energized in this circuit, opens contact 315 - in the circuit of the upper winding of relay RR2, which consequently de-energizes, closes contact 207 so as to short-circuit the small capacity capacitor 208 whereby the busy signal can be reconnected to the calling subscriber's line, and closes contact 209 to establish the talk circuit.

   The conversation circuit is then the following: starting from the station & called it, no 11, via conductor A, contact 93, capacitor f10, .contact 207, conductor 156, the contact <B> 117, </B> contact 153, conductor A12 to subscriber no.12 and return via conductor B12, contact 152, contact 115, conductor 151, contact 211, contact 209, capacitor 212, contact 92, conductor B to return to the station of subscriber no.1.1, the conversation circuit battery being supplied on the side of the calling party by the line relay LRI which, as will be seen, is connected to the drivers <I> A </I> and <I> B, </I> while the battery is powered,

   on the called subscriber's side, by relay BB2, which is connected to conductors 151 and 156. The subscribers can then continue, and when they have finished, the calling subscriber and the called subscriber hang up their calls. ceptors.

   When the calling subscriber hangs up his receiver, the line relay LRL de-energizes and opens the contact 94, which opens the circuit of the relays BL2 and IS making them, thus de-energized. Relay RL2 opens contact <B> 110, </B> thus allowing the ACH2 relay to de-energize.

   The 11CH2 relay de-energizes and opens the 111 contact, thus opening a blocking circuit for the SRA and SRZ relays, which de-energize thus. The opening of the contacts 153 and 152 opens the circuit -du relay BB2 which de-energizes and consequently everything returns to the normal state.

   However, assuming that the calling subscriber hangs up his receiver after the called subscriber hangs up his, the relay BB2 would de-energize and open the conversation circuit to contacts 209 and 207 and at the same time close contact 315, the exciter circuit of the BBC2 relay being thus established from the battery by the BBC2 relay via the contacts <B> 11-1, </B> 315 and 95, towards the earth.

   However, this circuit would have no effect, the relay BBC2 being short-circuited as a result of the de-energization of BB2. in the following circuit: earth, contact 95, contact 142, contact 147, contact 146, contact 216, contact 214 to the left terminal of the BBC2 winding, BBC2 winding, contact 114, contact 315, contact 95 to the Earth.

   It is therefore essential before the called subscriber can be effectively released that the calling subscriber has hung up his receiver, which is naturally customary use in the main automatic telephony systems.



  It can be seen that the foregoing description relates to the case where their supply groups are idle, and where a subscriber of a private office wishes to communicate with another local subscriber. Briefly, the operation can be summarized as follows: the subscriber's call device is actuated to send the impulses corresponding to digits 1, 2.

   The pulses corresponding to the first digit indicate that local communication is desired and therefore the main office line 43, 44 is activated and at the same time the call is transmitted to the second power supply group. @de bat terie G2.

       The subscriber then sends the pulses corresponding to the number 2 and tries the line @ of subscriber no.12, realizes whether this subscriber is busy or not 2t, -in the case where he is busy, receives the busy signal; if the set is free, the calling subscriber rings, until answered. After an answer, the conversation connection is established, and at the end of the conversation everything returns to normal.



  Suppose now that subscriber # 11 calls subscriber # 12 and the second battery power group G2 is busy, being used for another call. In this case, the trip relay RL2 will be energized and, consequently, when contact 81 is closed and the transfer relay de-energizes. <I> CHI, </I> a .circuit will be established for the ALS relay -as follows: earth, contact 40, contact 78, contact 79, conductor 80, contact 81, conductor 82, contact 83, conductor 84, contact 231, conductor 232 , relay ALS to the battery.

   The ALS relay energizes in this circuit and establishes a blocking circuit for itself at contact 283; at the same time, it opens contacts 48 and 51 and closes contacts 234 and 235. To contacts 47 and 234, it connects the conductor of the central office 43 to earth and to contacts 52 and 235, it connects the conductor @ from the office 44 through the resistance 236 to the .battery;

   at the same time on .contact 51, it disconnects the relay BBl and, consequently, the battery continues to supply the main office via the conductor 44 which is thus made, occupied, but then that the selector of the main office has only been moved up to the first floor, which is uncon nected, no other switches intervene and only conductors 43 and 44 and the associated switches in the main office are all occupied and returned inaccessible to. .other calls.

   Note that contact 49 is isolated from the pulse-giving circuit of contact 48, so that the next series of pulses cannot produce any new pulses at the main office. The ALS relay at contact 237 also establishes the following circuit: earth, contact 40, contact 238, upper winding of the FD relay, contact 237, conductor 240, contact 239 of the CRI relay, .contact 218, contact 68 of the relay <I> FRA, </I> contact 69 of the FRC relay, FRC relay, contacts 62, 63, 64, 65, 66, CRI relay to the battery.

   Currently the FD relay cannot be energized because its winding is short-circuited on the conductor 218 and the contact 67 of the ACHl relay. However, the ACH1 relay will de-energize very soon after a short time interval following its slowness in de-energizing, its circuit being open at contact 70, following de-energization of the CHl relay, which means that contact 67 is possibly open and that the exciter circuit passing through the upper bearing of the FD relay becomes effective.

   The FD relay is energized, blocks in the energized state at contact 941 and opens contact 238. The opening of contact 238 opens the circuit of the FRC and CRI relays and causes them to de-energize, so that the recording relays return to the normal state, ready to receive the new series of impurities. The FD relay at contact 75 prepares a blocking circuit for the ACIh relay at contact 563, it prepares the busy signal circuit over the conductor <B> 159, </B> and at contact 242 it prepares the test circuit as will be described later.



  It will be noted that the BB.1 relay de-energizes during the excitation of the ALS relay following the opening of the contacts 48 and 51 and consequently a contact is established for the BBCl relay via the contacts. ? 43 and 244, relay BBC1, resistor 245 to the battery.

   The BBCI relay in this circuit opens contacts 246, 247, 248 and 249 so as to prevent any disturbance of the existing connections which can be used when the next series of pulses are transmitted, and it is evident that the BBCl relay remains energized during the entire series of pulses. As a result of the BBI relay de-energizing after digit 1 has been transmitted, simply the excitation of BBC1 is maintained.

   Everything is now ready to put the dial on the second digit, which in this case consists of two pulses. The LRO relay reacts opens contact 49, which however does not produce: no effect following the opening of contact 48. It also temporarily opens contacts 34 and 41, but this has no effect, in the first case as a result. .of the. Leneur of relay RLl, .in the second case due to the fact that contacts 77 and 42 are open.

   However, a circuit is closed on contact 5 7 for the relay <I> CHI </I> as follows: earth, contact 40, contact <B> 57. </B> contact 58, contact 71, contact 72, relay <I> CHI </I> towards the bat terie. Relay <I> CHI </I> gets excited and establishes at contact 73 a blocking circuit for itself, independently of contacts 71 and 72.

    At contact 70, relay CHl establishes a circuit as it was previously established for relay ACHl, - from earth to contact 40, contact 70, ACHl relay to the battery, tan say that at contact 250 a circuit is prepared for relay BR1 as follows: battery, relay BHl. contact 250, contact 242, test conductor 243, which is successively connected to test conductors T11, T12, etc., since the relays <I> CRI, </I> CR2 are excited.

   The ACHI relay closes contact 67 and completes a blocking circuit for itself at contact 74 as follows: earth, contact 40, contact 75 - from relay FD, contact 74, relay ACHI to battery. The ACHI relay opens contact 72 which therefore prevents the CHI relay from energizing again after it has once been de-energized, although it is naturally blocked in energized state for any length of time. the series of pulses, via contact 73.

   The pulse conductor is also connected. through contact 73 to conductor 59, passing through contact 60, contact 61 to energize the FRC relay and. from there through contacts 62,; 63. 64, 65 and 66 to energize the CR1 relay. The FRC and CRI relays energize in this circuit and the FRC relay is stuck in the energized state in the circuit:

    earth, contact .10, contact 57, conductor 218, contact 68, .contact 69, FRC relay, contacts 62, 63, 64, 65 and 66, CRI relay to the battery. At the end of the first pulse, -the LRO relay is energized-again and closes contact 41 establishing a circuit for the FRB relay as follows: earth, contact 40, contact 41, contact 76, conductor 219, contact <B> î7, </B> lower winding of the FRB relay towards the battery.

   The FRB relay is energized, opens contact 60 and closes contact 220 and completes contact 331 with a blocking circuit for its lower winding. The following operation occurs when relay L170 de-energizes during the second pulse, when the following circuit is established:

   earth, contact 40, contact 57, contact 58, contact 73, CHI relay to battery, thus keeping the CHI relay energized, while a branch is established on conductor 59, contact 220, contact 221, relay <I> FRA, </I> contacts 222, 223 and 224, relay CR2 to the battery. Relay <I> ENG </I> gets excited and opens contact 68, thus causing de-energization of the FRC and CRI relays;

   <I> at </I> contact 230, a circuit is established for the upper winding of the FRB relay, which thus remains actuated independently of contact 77 which opens when the FRC relay de-energizes.

   The CR2 relay is also energized and opens the contact <B> 66, </B> disconnecting the CRI relay again, and prepare a circuit through 226 for the CR3 relay. The FR3 relay is blocked in the energized state in the following circuit: earth, contact 40, contact 67, conductor 218, contact 251, the FRC relay having been de-energized, contact 252, relay <I> FRA, </I> contacts 222, 223, 224, 225, relay CR2 to the battery.

   The relays <I> ENG </I> and CR2 are therefore kept energized and as this is the final impulse of the series, a test is made to ascertain whether the called line is busy or not. 'Assuming the called line is busy, there will be. earthing .du conductor TI2 as described above.

   A circuit for the occupancy relay BRI will therefore be established as follows: earth via @conductor T12, contact 253, conductor 243, contact 242, contact 250, relay BRI to the battery. The relay BR1 is therefore energized and blocked when energized in the following circuit: earth, by contact 40, contact 254, contact 255, relay BRI to the battery;

   this circuit being established when the CHI relay de-energizes at the. end of the series of pulses, the relay BRI then connects the conductor 160 actuating the occupancy signal to the earth, so that an occupancy signal is received through the intermediary of the conductor 159 and the contact 5 , 63 -of the FD relay as will be described later. The busy signal passes through capacitor 256 to the conversation conductor A from where it passes through contact 32 of the OTSII relay to the device of the calling subscriber, and informs him that the number he asks is busy.

   The subscriber then hangs up his receiver, thus producing @ de-energization & LRO which, in turn, causes de-energization of relay RLI, and opening of contact 40; after which the ALS relays, <I> OS, </I> <I> CHI, </I> FD, BR1 and BBCI get de-excited; the relays <I> ENG </I> and CR2 also de-energize;

    It should be noted that FRB had de-energized at the end of the second pulse, its blocking circuit on the lower winding having been opened at contact 7 7 when the FRC relay had been energized and its exciter circuit on the upper winding, opening; at contact 57 when the LRO line relay had been energized at the end of the second pulse.

         The interruption of the connection to the earth of the conductor 55, during the opening of the contact 40, produces the release of the OTS11 relay. while the opening of contacts 37 and 39 allows .au refilais C011 to de-energize; the whole set is now restored to normal and can be used by another subscriber.

         However, if the called subscriber was free, a circuit would be established as a result of de-energization of relay CH1 as follows: earth, contact 40, relay RR1, contact 257, contact 242, conductor 243, -contact 253, conductor @ test T12, relay <I> C012 </I> to, the battery. Relay RRl and switch relay C012 are cited in this circuit.

   Relay RR1 at contact 565 short-circuits the lower winding, from relay BBl to the battery; this delays the operation of the BBl relay and makes it insensitive to alternating currents. At the same time at contact 262, the upper winding of relay BB1 is shunted on resistor 263 to contribute to the above-mentioned effect. The RRI relay also opens the contact 224, allowing;

  thus. to the BBCI relay to become de-excited again; it closes the contact 258, completing a circuit of the earth and of the contact 40 by the contact 443, the contact 268, the upper rolling of the relay RR1 towards the conductor 157 which is connected to the battery.

    The ringing relay RR1 is therefore blocked in the excited state, and at the same time the ringing current returns by the conductor 1.61 which goes to the contact 259, contact 247 to the conversation conductor B, the contact 260, conductor B12 through the sound to extension @ of subscriber no.12, return via conductor A12, contact <B> 261, </B> contact 248, contact 262 and resistance 263 to earth.

   When. @ de-energization @ of the BBCl relay, the lower winding of the RRl bell relay is short-circuited to contact 264, but since it is blocked in the energized state by means of contacts 443 and $ 25,

      the subscriber's bell rings and when he unhooks his receiver to answer it, a circuit for the BBl relay is established as follows: earth, upper winding of the BBl refilais, contact 248, contact 261, conductor A1 \? . line to a subscriber station, conductor B12, contact 260, contact 247, contact 259 to the battery on conductor 161.

   Consequently, the relay BB1 energizes, opens the contact 443 to open the circuit, blocking the upper winding, of the relay RR1, which produces the de-energization of this relay. The relay BB1 also closes contacts 265 and 266, which establishes a conversation circuit on the conversation conductors A and B.

    The BBCI relay circuit is open at contact 2167 to prevent this relay from being energized again if a called subscriber hangs up first, in which case the BBl relay would trip and complete the original excitation circuit for the BBCI relay, this is not desirable, as the trigger must always be under the control of (the calling subscriber.

   When the subscribers have finished their conversation and the calling subscriber hangs up his receiver, a trigger occurs roughly as described previously, the only difference, in this case being that when the busy signal is received, relay BR1 does not need to be de-energized and neither does the relay BBCI, but apart from that the relays RL1, ALS, ACHl and F de-energize again as before. The BBI relay, which is used to

  feed the battery to the called subscriber's wire, becomes de-energized again, either because the called subscriber hangs up, if he hangs up first, or as a result of the conta: ets 261 and 260 are open lor--, de-energization: of relay CR2, so that the group of .battery power supply Gl is. returned to its normal state regardless of: hooking up, of the receiver by the subscriber, called.



  The next case to consider is that when subscriber # 11 tries to call subscriber # 12, the first battery supply group G1 is already in use for another call. In this case, when the LI-1 line relay operates, there will be no circuit to energize the OTS11 relay. The supply circuit of the OTSII relay, as we said previously, passes through contact 23, which is now open since the relay RLl is actuated,

   the relay RL1 being actuated all the time that the power supply group, battery Gl is used. Therefore, it will set up for the relay <I> LTS11 </I> the following circuit: earth, contact 27 of relay RL2 in the battery supply group G2, contact 28 of relay IS, resistor 29, contact 30, contact 31, lower coil of the relay <I> LTS11 </I> to the battery.

   The relay LTSI is energized in the circuit and closes a blocking circuit for itself via the contact 97, this blocking circuit acting when the relay RL2 is energized, as will be described later.

   During operation of relay LTS11, ii opens contact 26 so as to prevent the excitation of relay OTSl-I in the event that the battery supply group GI becomes free, closes contacts 92 and 93, connecting thus the LRL relay to the subscriber's wire. Then relay LRL energizes and completes at contact 94. a circuit for relay RL2 as follows: earth, contact 268 of relay SRI, contact 269 of relay IS, contact 94, relay RL2 to the battery.

   As a result, relay RL2 energizes and establishes a blocking circuit for relay LTSII as follows: earth, contact 95, upper coil of relay LTS11, contact 97, relays C011 to. drums. Relay C011 energizes, disconnects relay 111 and earth at contacts 22 and 21 respectively and is kept energized throughout the connection. The relay Lil de-energizes and opens contacts 25 and 30 - so as to open the circuit.

    primitive excitation for relay LTSII, relay RL2 closes: contact 2.1 establishing a circuit between conductors 232 and 84 preventing a call from being transmitted to group G2 as long as RL2 is energized. Likewise, it will be noted that IS cannot be excited by its upper winding, as long as RL2 is excited. Relay RL2 to contact 7.62 connects the. earth at conductor 158, so that, as described below, everything is prepared to start charging the battery.

   It also closes contact 98 to allow the transmission of impulses. Subscriber No. 11 then activates his dial to transmit a single pulse. As a result, the LRL relay becomes unoccupied, and a circuit is established as follows: earth, contact 98, contact 99, contact 100, contact 101, contact 102, contact 103, SRC relay, contacts 104, 105, 106, 107 and <B> 108 </B> relays SRO, SR8, SR6, SR4 and SR2 respectively to the SRI relay and the battery.

   The SRI and SRC relays are therefore energized and are blocked in the energized state via the following circuit: earth, contact 95, contact 111, contact 112, contact 109, SRC relay, contacts 104, 105, 106, 107 and 108, SR1 relay to the battery. In a connection @ of the pulse circuit, extending from the earth, contact 98, contact 99, contact 100, contact 101, relay CH2 to the battery,

   the CH2 relay is energized and establishes the following circuit for the ACH2 relay: earth, contact 95, contact 110, relay <I> ACH2 </I> to the battery. The ACH2 relay energizes in this circuit and closes contact 111 thus preparing a blocking circuit for the SRC and SRI relays as described above. At the end of the pulse, the relay LRL is energized again and a circuit is established as follows:

         earth contact 98, contact 123, contact 124, contact 625, lower winding @from the SRB relay to the battery: the SRB relay energizes and closes contact 133 to complete a blocking circuit for its lower winding and also closes the contact 125 and opens the contact 102. However, as there are no more other pulses, the excitation of the relay SRB does not cause any operation resulting from the closing of this contact.

   After a short installation, as there are no more pulses, the CH2 relay de-energizes. And after another short installation the ACH2 relay also becomes unoccupied. When this occurs, the circuit for relay RL2 is opened at contact 268, as a result of energizing idu re SRI, and at contact 270 as a result, energizing relay ACH2. As a result, relay BL2 acts in the following circuit:

   earth, lower winding of relay IS, contact 94, relay RL2 to the battery. The relay IS is energized in this circuit, opens contact 269 to prevent its lower winding from energizing again either by relay ACH2 or by relay SRI and opens contact 28 and closes contact 86, which do not. have no appreciable effect in this particular example and closes contact 137. When relay ACH2 is de-energized, contact 111 is open and opens the blocking circuit of the SRC and SRI relays.

   Consequently, these relays de-energize and contact 268 closes. However, this has no effect on the shorting of the lower winding of IS, the contact 2.69 being open. When the SRC relay de-energizes, contact '625 is open and therefore SRB <I> se </I> de-energizes, and the recorder returns to normal state. Everything is now ready for the transmission of the next digit, which consists of two pulses.

   The first pulse produces the de-energization of the - LRL relay and a circuit is established as follows: earth, contact 98, contact 99, -contact 100, contact 101, contact 102, contact 103, SRC relay. contacts 104, 105, 106, 107 and 108, .SRI relay to the battery.

   As a result, the SRC and SRI relays are energized as before, SRC. .au .contact 109 establishing a blocking circuit for itself by means of contact 101, relays CH2 --t ACH2 also being energized as: described above. However, the ACH2 relay is now blocked in the energized state when it energizes in the following circuit: earth, contact 95, contact 142, contact 147, contact 146, relay ACH2 to the battery.

   The circuit is now established for relay BR2 as follows: battery, relay BR2, contact 138, contact 137, contact 136, conductor 135, contact 134 to test conductor T11. The relay BR2 is energized, but it is only for the duration of the first pulse.

   At the end of the first pulse, the LRL relay energizes again and the contact 124 closes, so that the SRB relay is energized in a circuit. <B> already </B> @ described. When the LRL relay de-energizes at the start of the. second pulse, a circuit is established for the SRA relay, namely: earth, contact 95, contact <B> 111, </B> contact 213, contact 13-1, SR A relay, contacts <B> 127, </B> 128, 129, 130, SR relay? towards the battery.

   The SRA relay at contact 132, establishes a circuit for the upper winding - of the SRB relay independently of the 625 contact so that the SRB relay remains energized. In - the following circuit: earth, contact 98, contact 123, contact 101 , contact 133, contact 132, upper winding of the SRB relay to the battery. This circuit therefore only lasts during the second pulse and as soon as this pulse ceases, the SRA relay de-energizes.

   If the called subscriber was not busy at the moment, a circuit for relay BR2 would be established as follows: earth through conductor T12, contact 141, conductor 135, contact 136, contact 137, contact 138, relay 11R2 to drums. As a result, the relays BR2 would be excited when the pulse would be.

   When. de-energization of relay CH2 resulting from the fact that it no longer receives, impulse (lsion, relay BR2 would block in the energized state in the following circuit: earth, contact 95, contact 142,: contact 1.40, contact 143, rolls BR2 to the battery Relay BR.2 by closing contact 139 and thus putting contact 160 on earth would switch it on.

    transmission -of the busy signal, -so that the busy signal would be received through conductor 1-59, capacitor 209, capacitor 210, contact 93, to the calling party No. 11, thus indicating to the calling subscriber that the requested subscriber is busy with another call.

   But if subscriber no.12 is free, relay BR2 will not be energized and when relay CH2 de-energizes as described, the following circuit will be established: earth, contact 95, contact 145, lower winding of relay RR2 , contact 137, contact 136, conductor 135, contact 141, conductor T12, switch relay <I> C012 </I> to the battery.

   The relays C012 and RR2 are therefore energized in this circuit; relay C012 interrupts line relay L12 and interrupts earthing the conductors leading to subscriber station no.12, while relay RR2 opens contact 114, thus opening the excitation circuit of relay BBC2 which was established as follows when the relay RL2 .was energized: earth, contact = 95 contact, contact 315, contact 114, relay BBC2, resistance 113 to the battery.

   Relay RR2 further short-circuits at contact 564, the lower winding of relay BB2 towards the battery, and at contact 154 it shifts the upper winding of relay BB2. <I> to </I> earth via resistor 155. This considerably delays the operation of relay BB2 and makes it insensitive to alternating currents.

   As a result of the exextitation of the BBC2 relay, the lower winding of the RR2 relay is short-circuited to contact 148, but this relay does not become unoccupied, because it is blocked in the energized state in the following circuit: earth , contact 95, contact 315, contact 149, upper winding of coil RR2 towards the battery on conductor 151.

   Closing this circuit, as will be seen later, results in the AC current being connected in series, with the battery for conductor 161, so that it establishes a ringing circuit as follows: battery, ringing current via conductor 161, contact 150, conductor 151, contact 115, contact 52,:

  conductor B12, son of the subscriber and station of the subscriber no 12 to. by ringing this station, driver A12, contact <B> 153, </B> conductor 121, contact 117, conductor 1.56, contact 154, resistance 155 to earth, slums that a branch circuit extends to.

       the. earth through the upper bearing of relay BB2. The sound continues until the called subscriber picks up his receiver and closes the conversation drivers, after which a battery circuit is established through the windings of the BB2 relay, producing the output. this relay.

   At contact 315 of this relay, the circuit of the upper winding of relay RR2 is opened, thus producing the de-energization of this relay, since its lower winding is short-circuited at contact 148. At contact 214, the relay BB9 opens the circuit in which the BBC2 relay is shorted during the ringing period.

   He closes contacts <B> 207 </B> and 209, switching off the capacitor 208 and completing the conversation line, the battery being supplied at the subscriber called by the windings of the coil BB2 ,. When the subscribers have finished the conversation,

          the calling subscriber hangs up his receiver and thus allows the LRL relay to de-energize. This is followed by de-energizing Uu relay RL2 which, in turn, opens the circuit of relays CH2 and ACH2. The ACH2 relay opens the 111 contact, which produces the deexcitation of the SRA and SR2 relays. By becoming de-excited,

   relay SR2 opens contacts 1.52. and 153, allowing relay BB2 to de-energize and open contact 141 and allowing relay C012 to de-exert. The whole thing returns to the normal state. It should be noted that the triggering is roughly similar in the case where the calling subscriber hangs up his receiver after receiving the busy signal. We will notice.

    that this description is essentially identical to the description of the first arrangement in which the subscriber., after having transmitted 1c, the first digit 1 is switched to the second group G2, except that in this case the registration on the dial of digit 1 as the first digit is necessary to activate the relay IS and to bring the battery supply group G2 to the state that it would have been brought by the primitive excitation: de. 1S via:

  of the GL group It would be advisable to consider here the case in which the first group G1 is occupied, but subscriber 11 requests a number of the main office. When it starts to establish the communication, it is connected to the G2 group in exactly the same way as described when it wanted to communicate with the subscriber no.11, and the G1 group was busy, but in this heap. , the first digit no longer consists of a single pulse, but of a number greater than one, for example four.

   In this case, the first impulse produces exactly the same operations as those described above, namely that at the start of the impulse the SRI and SRC relays are energized, the CH2 and ACH2 relays are energized and remain energized throughout. sending pulses, while the SRB relay is energized at the end of the first pulse.

   At the start of the second pulse, a circuit is established as follows: earth, contact 98, contact 123, contact 101, contact 125, contact 126, relay SRA, contacts 127, 1.28, 129 and 130, relay SR2 to the batterio. The SRA and SR2 relays are energized in this circuit,

   the SRA relay opens the contact <B> II A </B> thus allowing relays <I> SRC </I> and SRI -to get de-excited. Relay SR2 opens at contact 108 the circuit of relay SRI and in its place connects relay SR3 to contact <B> 271. </B> The SR relay <B> A </B> establishes a block circuit; 7th for itself, namely: earth, contact 111, contact 213, -contact 131, relay SRA, contacts 127, 1.28, 129, 130, relay SR2 to the battery.

    The SRA relay completes at contact 132 a circuit for the upper winding of the SRB relay, by contact 101, contact 123, contact 98 to earth for the duration of the second pulse, while at contact <B> 272 </B> a circuit is established for relay BR2 as follows: earth, contact 95, contact 273, contact 272, relay BR2 to the battery. The relay BR2 is energized and locks in the energized state in the following circuit:

   earth, contact 95, contact 2.73, contact 274, relay BR2 to the battery. As a result, relay BR2 remains energized regardless of the number of pulses transmitted by the dial. But the subscriber will not hear the busy signal, since his calling device is still in use. When relay BR2 is energized, it opens contact 99.

    When the second pulse ceases, the SRB relay de-energizes as a result <B> -de </B> '- opening of contact 101 and: opens the blocking circuit of relays SRA and SR2. At the start of the third pulse, the SRC and SR3 relays are energized - in the same way that the SRC and SRI relays were energized by. first impulse.

   The SRC relay opens the SR3 relay circuit. This relay SR3 is not energized and the relay SRC is blocked in the energized state by the contacts 109 and 112. In the same circuit as during the first pulse.

   When the third pulse ceases, the SRB relay is energized by the contact 625 and its lower winding, and at the start of the fourth pulse the SRA relay and the SR4 relay which is now connected to the contact 275 instead of the SR2 relay , is energized, and the SRC and SR3 relays de-energize. At the end of the.

    fourth pulse, the SRB relay de-energizes and after a pause, the CH2 relay de-energizes and opens contact 1'23. After a short pause, relay ACH2 de-energizes and opens contact 111, whereby relays S'RA and SR4 de-energize and therefore all relays are brought to. normal state.

   The subscriber can continue to transmit digits to the dial without listening to the busy signal, but this has no effect since contact 99 is open, so that the first impulse cannot pass to the telephone. counter relay via the circuit: earth, contact 98, contact 99, contact 100, contact 101, contact 102, contact 103, SRC relay, contacts 104, 105, 106, 107 and 108 to the SRI relay and to the battery .

   It is evident, therefore, that no impulse can be more effective, so that if the subscriber picks up his receiver, he hears the busy signal which has been transmitted by the relay of oc cupation BR2 connecting the earth to the contact 139 with the conductor 160 and receiving the occupancy signal in return by the conductor 159, the capacitor 208, the capacitor 210, the contact, 93 to its station via the line circuit. of the subscriber.

   He then knows that he cannot obtain the number he wants and hangs up his receiver, after which the relay LRL and RL2 in turn de-energize and allows the relays BR2 and BBC2 and BB2 to de-energize, relay LTS11 and relay C011 also being de-energized as has been described previously.



  Note., That when relay RL1 or relay RL2 are energized, the earth is linked to conductor 158 connected to the group of RBC bell relays, occupancy signal and -de: cha.rge, shown- in fig. 7. The relay RL1 produces this result by closing the contact 36, while the relay RL2 cooperates there by closing the contact 162.

   When this happens, the relay <I> CH </I> is energized, the CI7 relay closes the oonta; and 163 and establishes a -circuit for the CC relay which then completes a blocking circuit for itself through the contacts the 65 and 168.



  But nothing more happens until conductor 158 is no longer grounded, after which the relay <I> CH </I> de-energizes and, together with the DC relay, establishes a circuit for the MR relay on contacts 166 and 164.

   As a result, the MR relay is energized and remains energized until the: load conductor 15'8 is again connected to earth following a call from a subscriber, after which the: contact 164 is open and the MR relay de-energizes, or until the high voltage HVR relay, the circuit of which is closed, on contact 167 of the MR relay is energized. This high voltage relay is a relay which is energized only when the voltage of the battery has reached a determined voltage, at,

  above the normal voltage during the charging of the battery, which means that it can only be energized when the battery is sufficiently charged and in this case it: opens the: contact 168, or thus viewing the Blocking circuit for the DC relay which in turn opens the circuit for the MR relay.

   It will thus be appreciated that in neither of the two cases, that is to say when calling a subscriber or when the battery is fully charged, does ide la charging occur. ,drums. This arrangement has the advantage that charging never occurs while a conversation is engaged, while at the same time the battery is kept fully charged between the conversations. The MR relay, as we have already indicated, is intended to start the: charging and the: charging device will be. -: briefly described below. We will first assume that there is a DC power source available.

   In this case, fuses Dl and D2 will be placed therein and the charging circuit will be established as follows: positive pole of the energy source connected to conductor 170, contact 171, fuse d2, conductor 172, bo - delay bine 173 towards the positive pole of the battery, while the negative pole of the battery is connected by the fuse of 1 to the conductor 174,

   contact 175 and conductor 176 connected to the negative pole of the energy source. However, if the local power source supplies alternating current, it is necessary to provide a rectifier, which is obtained by the polarized relay PR.



  Note that when the MR relay is energized, it closes the contact 1.69, establishing a circuit for the PR relay as follows: earth, battery, resistor 177, contact 169, lower windings, of the polarized relay PR on earth.

   These windings do not produce any operation of the relay on their own, but simply serve as polarizing windings. Another circuit is established as follows: conductor 170, capacitor 178, contact 179, upper windings to the polarized relay PR, contact 180 to conductor 176. Therefore, the alternating current passes through these windings and forces it. armature .du polarized relay to alternately close the contacts 181 and 182 according to the frequency of the alternating current.

   Current 181 is currently inactive, but contact 1'82 directly connects earth through contact 183 of relay MR and low-voltage winding L id of the transformer, to the negative pole of the power plant battery. Under these conditions, that is to say when charging at. 1 ', ide help: current: alternative, the dl and d2 fuses are removed.

   The high voltage winding H: of the transformer is, therefore, directly connected by passing through the conductors 170, 176 - of the power source, to the contacts 171 el, 184 respectively. This produces the generation of an alternating current of the same frequency and of an appropriate voltage, in the low voltage rolling L of the transformer. Normally this would simply serve to ensure the passage of alternating current through the battery.

   However, by a suitable arrangement of the windings .du relay PR, the contact 182 is closed only for a half-cycle, that is to say the half-cycle during which the direction of the current is likely to charge. battery; during the other half cycle, contact 182 is open and therefore no charging occurs. The re suiltat is therefore an efficient charging of the battery.



  It will also be noted that during excitation of the relay BB1 or of the relay BR2, the earth is connected by contacts 185 and 139 respectively to the conductor @ for setting in motion, of the occupancy signal 160. This has the effect of energizing relay 13 on the contact. <B> 186 </B> of the relay <I> RB. </I> This relay 13 is energized and closes contact 187 to energize relay 112.

   The relay 112 is energized and closes through the intermediary of the contact 188 a circuit for the relay 11, while a circuit is established through the intermediary of the contact 189 of the earth, by the conductor 160, by @ contact 189 to the LV occupancy signal relay, resi-3- ta.nce 190 to. drums. The LV relay is.

    energized and, by the closing of its contact 191, it is short-circuited so that it immediately de-energizes and intermittently re-energizes, thus producing the in termittent charging and discharging of capacitor 192 and sending a sound through the conductor 159. The relay 11, when it is energized, closes the contact 193 in parallel: with the contact 189 and at the same time closes the contact 194.

   Contact 194 completes a short circuit through relay 113, resistor 195 preventing the battery from being shorted. As a result, relay 13 de-energizes after an interval, because it is slow-acting, and because it is made even slower by short-circuiting its windings. By its triggering, it opens contact 187 which opens at contact 196 the rolling of relay 12 in order to short-circuit it.

         Since switch springs are provided to make this short circuit effective, in order to decrease the tripping time of relay 12, a resistor 197 is provided to prevent the battery from being connected directly to earth. Likewise, when relay 12 trips, it opens contact 188 and closes contact 198, which bypasses relay 11.

   Resistance 199 is intended for the same purpose as resistance <B> 197. </B> that is to say to prevent shortcircuiting d (@ the battery while contacts 188 and 198 are momentarily closed.

   For a while the contacts 199 and 193 are open and the intermittent operation of the LV relay ceases, thus giving an interruption in the busy signal, but as soon as the contact 194 opens again, the relay 13 is energized and produced. re-energization of relay 12, which in turn produces re-energization of relay 11, after which the relays successively de-energize, as stated above, and consequently the occupancy signal is transmitted intermittently, the cycle operation of relays 1.1,

   12 and 13 continuing as long as the earth is connected to the occupancy signal transmission conductor 160. It can thus be seen that the earthing of the occupancy signal conductor 160 produces the intermittent connection of a current, busy signaling with conductor 159 which is isolated from all the batteries and from the mi ses to earth by capacitor 192.



  It will have been noticed that each time one of the ringing relays RR1 or BR2 is energized, the upper winding of these relays is connected to the conductor 157 which passes through <B> le </B> @ ringing relay <I> RB </I> down to the battery. Each time this occurs, relay RB is energized and establishes in contact 200 a circuit for relay 13 which, in turn, causes the work of relays 12 and 11 in the manner described above.

   Consequently, these relays operate intermittently and, although the closing of contacts 189 and 193 has no effect because the conductor activating the occupancy signal 160 is not connected to earth, the contact 201 is open and closed intermittently, and at the same time the contact 202 of the relay <I> RB </I> completes a circuit through, from contact 203) through the upper windings of relays PR, contacts 204 and 205: of relay 111R, and resistor 177, to the battery.

    Therefore, active windings act in one direction for grounding through contact 181 to short circuit the active winding of the polarized relay, which relay therefore opens contact 181, removing it. short circuit, and therefore the polarized relay energizes again.

       The oscillation of its armature produces an intermittent closure of the connector 182, so that the office battery is permanently connected in series with the low voltage winding L of the transformer, the current DC must pass intermittently through the winding L via contacts 1.82 and 201.

   This produces an AC coverage in series with the battery transmitted through contact 206 to capacitor 161 of the generator which is connected to the talk leads each time the relays RR1 or RR2 are actuated; this current is intermittent depending on whether the contact 201 is green or closed. A variant & assembly for the generation of a current - ringing by the battery - of the office, is represented. In the fis. 8 and although this arrangement is described for the bell only, it is evident that by employing a suitable switching relay such as: 11R, it could easily be applied to loading.

   However, it will be sufficient to understand the operation by. simple description from the point of view of current generation: ringing. When contact 202 is closed, a circuit is established for relay PR as follows: earth, contact 202, lower winding of polarized relay PR to battery. The polarized PR windings are energized in this circuit. The active windings are excited. In this cir cuit following: earth, contact 202, contact 408. resistor 412 actuating the windings of the relay PR, windings 404 - from the transformer to the battery.

   At the same time, it will be noted that a branch circuit passes through the bearing 405 to the tba.tterie so that a stronger current passes through the winding 405 than through the winding 404. However, the current through 404 is sufficient for the polarized relay to act on its armature and close the right contact -1: 06, after which a circuit is established for the relay 407 as follows: earth, contact 202, contact 406, contact 408 , relay 407 to the. drums. The relay 407 is energized and is blocked in the energized state by the contact 409 and the earth on the contact 202, simultaneously opening the contact 403 and closing the contact 410.

    closing: contact 406 earths, via contact 410, on the right side of winding 404. As a result, a current flows from the battery through the left-hand bearing 405, the upper windings of the relay polarized PR, contact 410, contact 406 and contact 202 to earth. This is to say that a reduced current passes through the winding 405 and a current in the opposite direction passes through the upper windings, while at the same time, through the direct connection to earth. the right winding 404, a reinforced current passes through this winding.

   Strengthening current 404 and decreasing current 405 assist each other in their inducing effect on the coil SC. The polarized relay PR, acting in this reverse direction, closes contact 411 thereby grounding through contact 202 the left side of the upper windings of the polarized relay and thus increasing the current through winding 405, decreasing the current through 404 and returning the current through the windings of the polarized relay PR.

   This reversal produces a new action of the armature and in this way a very efficient generation of alternating current is obtained which is created in the secondary coil SC connected to the ringing circuit where it can be used at the time. wanted by the calling subscriber to ring the bell he wants.



  A communication with the main office will now be described. It will again be assumed that the two groups of battery supply are free and that the subscriber makes the connection with the group G1 in the manner previously described, but in the present case, since the call is made to a main office, the first series of taxes transmitted does not consist -not of an impulse, but of a larger number.

   Suppose, for example, that this number is four; after the first pulse, when the CRI relay has been actuated in series with the FRC relay, it is blocked energized by contacts 69 and @ 68, conductor 218, contact 67 of the ACHI relay., contact 40 towards the Earth. As the pulse does not stop at the first digit transmitted, the relays <I> CHI </I> and ACHI remain activated.

   At the end of the first pulse, the FRB relay energizes by the contact 77 of the FRC relay and its lower winding, and at the start of the second pulse, the contact 57 is closed and a circuit is established as follows : earth, contact 40, contact 57, contact 58, contact 73, conductor 59, contact 2'20 of the FRB relay. relay contact 221 <I> FRA, </I> FRA relays, contacts 222, 223, 224, 22'5 of relays CR9, CR7, CR5, CR3, respectively, and relays CR2 to the battery.

   CR2 relays and <I> ENG </I> are excited in this circuit; relay FR A opening contact 68 @ so as to force FRC and CRI to de-energize: relay CRI is also switched off by relay CR2 to contact 66, and relay CR3 is connected in its place to contact 226 .

   Relay <I> FRA, </I> when energized, closes contact 2.27, thus establishing a circuit for the busy signal relay BR1 as follows: earth, contact 40, contact 228, contact 227, relay BRI to ' drums. Consequently, the relay BRl is energized and blocks in the energized state in the circuit by the contacts 229 and 228 independently of the contact 227, but does not transmit to contact 562 the occupancy signal, because the contact 563 - of the FDI relay is open.

   Consequently, the FRB relay does not de-energize when the contact 77 is open when the FRC relay is de-energized, because it is kept energized by its upper bearing, the contact 230 of the relay. <I> ENG </I> to earth via conductor 59. At the end of the second pulse, when conductor 59 is: disconnected from earth, the FRB relay de-energizes.

   At the start of the next pulse, a circuit is established for the FRC and CR3 relays as follows: earth, contact 40, contact <B> 57, </B> contact 58, contact 73, conductor 59, contact 60, contact 61, relay FRC, contacts 62, 63, 64, 6 @ 5, 22'i6, relay CR3 to the battery.

    The CR3 and FRC relays are then energized, the FRC relay opens the .contact 251, thus triggering the relays. <I> ENG </I> and CR2, while the CRC relay opens contact 225 and closes contact 276, thus connecting the relay <B> CRI. </B> A ^, la. At the end of the third pulse, the FRB relay is energized in the following circuit: earth, contact 40, contact 41, contact 76, conductor 219, contact 77, lower winding of the FRB relay towards the battery.

   At the start of the fourth pulse, a circuit is established as follows: earth, contact 57, contact 58, contact 73, conductor 59, contact 20, contact 221, relay <I> FRA, </I> contacts 222, 2 923, 224, 276, relay CR4 to the battery. The CR4 relays and <I> ENG </I> are blocked in the excited state in series by contact 252, the contact <B> 251, </B> contact 67 and contact 40 via the earth, opening:

  on contact 68, the excitation circuit of the relays CR3 => t FRC which de-energize thus, ales FRP relays being kept energized as described above for the second pulse.

    Since there is. plus other pulses, the relay <I> CHI </I> de-energizes. After a short interval and opens contact 73; it also opens contact 70 and allows the ACHI relay to de-energize. During this period, four pulses were sent to the main office by relay LRO which opened contact 49 four times. Subsequent pulses are unable to activate the counter relay because contact 71 is now open and therefore neither the relay <I> CHI </I> nor the counter relays can be activated again.

   In addition, the de-energization of the ACH1 relay turns contact 67 on, so that the relays <I> ENG </I> and CR4 also de-energize, restoring the count relays to normal. The subscriber can therefore continue to send the impulses to operate the switches at the main office in the ordinary manner as it will be. : described below: a.next by referring to fi-. - 9, 10 and 11.

   To trigger the connection when he has finished the call at the main office, the subscriber simply hangs up his receiver, and the LRO relay circuit opens, the relay de-energizes and opens contact 49, thus releasing the switch. from the main office. The LRO relay also opens the circuit of the RLI relay which de-energizes and opens the contact 40, triggering the OS, BBl and OTS11 relays. As all the other relays are triggered, the normal state of the GI group is re-established and it can be used by another subscriber.



  The next operation that we will describe is the one in which the main office subscriber requests a local subscriber. In this case, it transmits the number of the private branch office and occupies a repeater there, as described in reference to fi-. 9, 10 and 11, so that the battery is supplied by the conductors 43 and 44 so that a circuit is established for the relay LRI as follows:

       battery by driver 43, contact 45, LRI relay, contact 46, conductor 44 to earth, earth at main office. Relay LRI, when energized, closes contact 277 thereby energizing relay RL1, opens contact 58 and closes contacts 278 and 279. Relay RLI. closes contact 40, which makes a circuit for the BBCI relay as follows: earth, contact 40, contact 443, contact 244, relay BBC1, resistor 245 to battery. The BBCI relay is then energized and opens contacts 246. 247, 248, 249 and 264.

   A second circuit closes at contact 40 as follows: earth, contact 40, contact 278, lower winding of the FD relay to the battery. The FD relay is then energized and locks in the energized state in the following circuit: from the battery, upper winding. From the FD relay, contact 2.41, to earth. Relay D prepares the occupancy signal circuit for contact 563. At. contact 242 is connected to a test circuit which, for the moment, remains ineffective, contact 228 is open and contact 75 closed.

   The subscriber at the main office does not transmit the first digit, but transmits the second digit of a subscriber @ from the secondary office, for example, assuming he: desires subscriber no.12, he transmits the digit 2 Accordingly, when the first pulse is received at the secondary office, the battery will cease to be supplied by conductors 48 and 44 and the LRI relay will be energized.

   The following circuit will therefore be established: earth, contact 40, contact 57, contact 58, -contact 71, contact 72, CHI relay to the battery, a bypass taking place on conductor 50, contact 60 of the relay FRB, contact 61, relay FRC, contacts 62, 63, 64, 65, 66, CRI relay to battery. The FRC and CRI relays are energized in this circuit and are blocked in the energized state by contact 69, contact 68, contact 218, contact 67, contact 40 to earth, relay CHI when energizing having closed as previously the contact 70, which establishes a,

  circuit for ACHI relays as follows: earth, contact 40, contact 70, ACHI relay to battery. Consequently, the ACHl relay is energized and closes the coutaet 67.

   The FRC relay also closes contact 77, so that. at the end of the first pulse, when relay LR1 is energized again, the following circuit is established: earth, contact 40, contact 279, contact 219, contact 77, lower winding. @from the FRB relay to the battery.

   The FRB relay is then energized, closes the contact 231 and the contact 220 and / or the contact 60 - so that when the relay LRI is energized for the following series of pulses the following circuit is established:

    earth, contact 40, contact 57, contact 58, contact 73, conductor 59, contact 220, contact 221, relay <I> ENG. </I> contacts 222. 223, 224 and 225, relay CR2 to the battery. The relays <I> ENG </I> and CR2 are energized. Then and contact 68 is open thus allowing the FPC and CRI relays to de-energize: the contact <B> 2.52 </B> is closed so as to block the relays <I> ENG </I> and CR2 in the excited state, by contact 251, 1F contact 67 and contact 40 to earth.

   The FRB relay is kept energized by its upper bearing, contact 230 - of the relay <I> ENG </I> to earth through conductor 59. At the end of the second pulse, the FRB relay de-energizes and shortly after, as there are no more pulses to be received, the CHI relay de-energizes. If subscriber no.12 had been busy, a circuit for the BRI relay would have occurred before this as follows: earth, by conductor T12, .contact 253, contact 242, contact 250, relay BRI to the battery, and when the relay <I> CHI </I> de-energizes, a blocking circuit would be completed for the BR1 relay as follows:

   earth, contact 40, contact -? 54, contact 253, relay BR1 to the battery. Consequently, the relay BRI connects the earth by the contact 185, to the conductor 160, to activate the occupancy signaling device, connecting the occupancy signal through the conductor 159, the contact 563 of the FD relay , contact 562, through condenser 256 and conductor A to the station of calling subscriber no.11.

   On the other hand, if the called subscriber had been free, a circuit would have been established for relay C012 as follows: earth, lower winding of the RRI relay, contact 257, contact 2'42, conductor 243, contact 253, test lead T.12, relay <I> C012 </I> to the battery.

   The RR, I relay and the relay <I> C012 </I> are energized in series, the C012 relay is energized to disconnect the L12 line relay and the earth. Of the line of subscriber no.12 and the relay of its nerie is energized to complete. a circuit as follows:

   earth, contact 40, contact 258, contact 443, upper winding of relay RRI_, conductor <B> 1.57 </B> to the battery by passing the relay actuating the circuit, of its own, so that the! Aliern.ative current and the battery in series are connected by the conductor 161, the contact 259, the:

  contact 247, contact 260, conductor B12 of subscriber station # 12, conductor A12, driver 261, contact and 248, contact 262, resistor 263 to the battery. Consequently, the subscriber's bell is activated and when the latter removes his receiver, a circuit is established for the relay BBl. Whose upper bearing is connected in a branch of the circuit which has just been described, resistance 263.

   The BBI relay. by energizing, opens contact 443 to produce de-energization of relay RR1 and at the same time to prevent relay BBCI from being energized when relay RR1 de-energizes. The buzzer is interrupted by the opening of contacts 258 and 259 when relay RRI de-energizes, contact 279 is closed to connect the lower winding of relay BB1. The BBI relay closes contacts 265 and 266 -in the conversation-circuit which is established as follows, conductor 44.

    contact 45, contact 280, capacitor 281, contact 265, contact 248, contact 261, conductor A12, subscriber station, conductor B12, contact 260, contact 247, contact 279. contaict 266, capacitor 282, contact 46. driver 44 to the main office.

   When the subscribers have finished speaking, the subscriber @ calling at the main office, which hangs up its receiver, thus releases the subscriber at the secondary office, and disconnects the battery of conductors 43 and 44, by producing so the. de-energization of the LRI relay. The LRl relay, by de-energizing,

      opens on contact 278 the circuit! of relay FD and on contact 277 the circuit of relay RLl. Relay RLl de-energizes and opens on contact 40 the circuit of relay ACHl which is also or green by the relay <I> PD </I> to contact 75, so that relay ACHl de-energizes and opens contact 67 thus allowing relays FRA and CR2 to de-energize.

   The opening of contacts 260 and 261 allows the BBl relays to de-energize, while the opening of the contact <B> 263 </B> allows relay C012 to de-energize. It will thus be realized that all the relays are now returned to the normal state and that the battery supply group C1 is free for other calls.



  Of course, various modifications can be made to the arrangement of the counter relays shown in fig. 4. A variant is shown in l z fig. 6, in which the relays <I> ENG </I> and FRC are eliminated, the functions of said relays being performed by contacts with the individual relays of the.

       chain. The resemblance between these two figures will be obvious once it has been understood that the contacts 300, 301, 302, 308 and 304 are equivalent to the contacts 77 of the FRC relay, the contacts 305, 306, 307, 308, 809 equivalent to the contact 230 @ relay <I> FRA, </I> contacts 310, 311, 312, 313 equivalent to contact 61 of the FRC relay, while contacts 314, 315, <B> 316, </B> 317, 318 are equivalent to contact 69 of the FRC relay, contacts 319, 320, 321, 322, 323 are equivalent to contact 221 of the relay <I> ENG </I> and contacts 324, 325, 326, 327, 328,

   .equivalent to contact 252! of the relay <I> ENG. </I> The other relay contacts in fig. 6 are designated by the same reference letters as in FIG. 4 so that the relationship between this series of meter relay chains can be easily established. It will be remembered that the conductor 59 is connected to earth as soon as the line relay LRO de-energizes after the first pulse. The driver- <B> 218 </B> is always connected to earth, as long as relay ACII is energized and conductor 219 is re-linked to earth between the interrupts.

   The conductors 80 and 8 ?, 218 and 240 and the conductors connected by the contact 329 serve exactly the same purpose as the conductors bearing the same reference numbers and those connected by the contact 227 of fig. 4.



  To understand the operation, it will be assumed that four pulses are transmitted. Immediately the LRO line relay de-energizes at. the first pulse and a circuit is established as follows: earth, via the conductor 59, contact 60, contacts 62, 63, 64, 65, 66, CRI relay to the battery.

   The CRI relay is energized and closes a blocking circuit for itself on the .contact 314 in the following circuit: earth, by the .conductor 218, contacts 323, 313, 322, 313, 321, 311, 320, 310, <B> 319, </B> 314, CRI relay to the battery. At the same time, it closes contact 300 so that at the end of the first pulse, conductor 219 is connected to. earth, a circuit is established for the lower winding of the FRB relay as follows: earth, conductor 219, contact 300, lower winding of the FRB relay to the battery.

   As a result, the FRB relay is energized, opens contact 60 and closes contacts 220 and <B> 231. </B> At the start of the next pulse, conductor 59 is earthed again, this earthing extending through contacts 220, 222, 223, 224, 225, relay CR2 to da batte rie. Relay CR2 is energized, opens contact 319 allowing the CRI Ue relay to de-energize and completes a blocking circuit for itself as follows: earth, conductor 218, contacts 323, 3 <B> 1 </B> 3, 322, 312, 321, 311, 320, 310, 324, CR2 relay to the battery.

    Relay CR2 opens contact 66 and closes contact 226; it also closes contact 305, thus completing a circuit for the upper winding of the FRB relay as follows: earth, via the conductor 59, contact 305, in upper bearing of the FRB relay towards the battery.

   Note that the FRB relay is kept energized from the end of the first pulse to the beginning of the second, by its lower winding, then, when contact 300 opens after the CRI relay has been de-energized, the FRB relay remains energized until the end of the second pulse by its upper winding in the circuit described above.

   When the earthing of conductor 59 is interrupted (- to <B> the </B> end of the second pulse, this last circuit is open and the FRB relay de-energizes, the earthing effected between the second and the third pulse to conductor 219 having no effect this this time because all the contacts 301, 302, 303 and 304: have opened. At the beginning of the third pulse, the conductor 59 is again earthed, now passing through the contacts of the primitive circuit 62, 63, 64, 65, but this time passing through the contact 226 to the relay. CR3 and the battery.

    Relay CR3 energizes, opens contact 310 to trigger relay CR2 and closes contact 315 to establish a blocking circuit for itself as follows: earth, conductaar 218, contacts 323, 3 <B> 1 </B> 3, 322, 312, 321, 3 <B> 1 </B> 1, 320, 310, 315, CR3 relay to the battery.

   Relay CR3 opens contact 225 and closes contact 276, it also closes 4th contact 310 to prepare a new: excitation circuit for relay FRB. Therefore, at the end of the third pulse, conductor 219 is grounded by the contact <B> 301, </B> the lower winding - of the FRB relay and; battery. The FRB relay is energized, opens the contact <B> 60 </B> and close contact 220; it also closes contact 231.

   At the beginning of the fourth pulse, the conductor 59 is again earthed, this time passing as for the second pulse, through contact 220, contacts 222, 223, 221, but this time through contact 276 and the CRI relay to the -battery.

   Relay CP.l is energized and blocks energized in the following circuit: earth, conductor 218, contacts -323, 32 <B> 2 </B>, 3 <B> 1 </B> 2, 32 <B> 1 </B>, .311, 3 <B> 2 </B> 0, 310. 325, CR relay! to the battery; he opens contact 320 to produce the. de-energization @ of relay CR3 and closes contact 306, thus completing a circuit for the upper winding of relay FRB. The FRB relay remains energized by the reset. the earth of the conductor 59 and de-energizes at the end of the pulse.

   It will be understood from the above .comment the subsequent pulses will actuate the relays CR5, CR6, CR7, etë. To trigger the counter relays: so that they can return to the normal state, it is simply necessary to cut the earthing of conductor 218.



  So that one can understand how calls are transmitted from a subscriber from a main office to a secondary office over the long distance line <I> TL </I> including conductors 44 and 13, and also the. how calls should be forwarded from a secondary office over the long distance line <I> TL </I> to. a subscriber: from the main office, -on will report. first to, fig: 9. The various operations will then be described with reference to fig. 10 and 11.



       We first assume that a call arrives via conductors 43 and 44. This call reaches the group of relays RG to which a TLS interurban line switch is connected. When the battery is powered by a trunk line through the relay group, the trunk line-TLS switch operates to choose. a first selector D at the main office;

   Therefore, <B> this </B> first selector D responds to the first series of pulses and searches for a second free selector E. This second selector E responds to the following series of pulses and then searches for a free connector F which responds to the following two series of impulses and establishes the. connection with the desired subscriber wire. It will be noted that the operations of the first selector D, of the second selector E and of the connector F are normal, and are well known in telephony.

   However, if the call comes from a subscriber at the main office, when he lifts his receiver, his SLS line switch will operate to choose a first free reader such as D. The selector D react < <to the first series of pulses transmitted and will automatically search for a second selector E cond. The second selector will then respond to the next series of pulses, and since we assume the call is for a local subscriber, it will go up at a certain level and will choose a desktop selector to be SES.

   The SES secondary office selector is arranged to respond to a series of pulses only and, depending on whether a trunk line is chosen such as <I> TL </I> be busy or not, it will give the busy signal or transmit the call on the in terurban line through the relay group RG which converts the normal pulses from the subscriber to battery power pulses suitable for operating the secondary office device.

   The last digit of the secondary office number, which contains exactly the same number of digits as a primary office number, is then received in the manner described by the secondary office to choose from in that secondary office. the line of the desired subscriber.

   Returning to fig. 10 and 11 in which the briefly .described circuits are shown, .on will note that the call arriving by conductors 43 and 44, which are indicated by connecting the battery to. through these conductors to the main office, as he has. described above, will energize the LRAI line relay. As a result, the LRM relay is energized, closes contact 505 and completes the circuit for the relay:

  BRIL RRM tripping. is energized and closes contact 510, which completes a circuit as follows: battery, LRT relay, contact 513, contact 510, contact 51.1, relay RT1l, contact 507, contact 51.8 to earth. The LRT relay is then energized.

   The RRM relay, when energized, also opens contact 509, - disconnects the SRM switching relay and closes contact 508 connecting earth @ conductor 545, thus preventing the trunk line from being taken by a SES secondary desktop selector. The RRM relay also closes contact 546.

   The LRT relay, when energized, closes contacts 520 and 544 and this completes a test-circuit as follows: conta: and test 5.17 of selector D, wiper 548, contact 516, contact 544 and contact 519. JILS magnet towards the battery.

   In the event that the selector on which the wipers 548, 549 and 550 rest were occupied, earth would be connected to the test contact 547 which is connected; the wiper 548 and, therefore, a circuit would be established for the magnet of JILS synchronization which will run intermittently as long as slider 548 is touching. a contact connected to earth.

   However, we will assume that the first selector D is free and in this case the SRT switch relay will be energized in the following circuit: earth, contact 590, SRT relay, contact 519, JILS magnet to the battery. The SRT relay 'is shorted and cannot be energized in this circuit as long as the slider 548 is grounded, so the SRT relay is energized only when a free selector is encountered. .

   Likewise, the resistance of the SRT relay is chosen such that the JILS magnet cannot be excited in series with it. The SRT relay is energized, opens contacts 513 and 518 allowing the LRT relay to de-energize and closes contacts 514 and 517, thus extending the connection to the first selector D. The operation of selectors D. E and F is correct. known and it is unnecessary to describe them.

  * Suffice it to say that when selector D is energized, the line relay also energizes, connects the trip. Trip relay which, in turn, connects the earth with contact 547, thus completing a circuit. blocking for the STR relay outside of contact 520, this circuit being completed before contact 520 is opened, because the LRT relay only de-energizes slowly. A circuit is then established as follows: earth, contact 547, wiper 548, contact <B> 515, </B> SRT relay, constant <B> 519, </B> IULS magnet towards the battery. The next series of pulses are received by the line relay.

   The selectors D and E are: of the well-known type operating in a rotational fashion, then in a vertical direction so that the first series of pulses force the rubbers of the first selector D to rise by one level, according to the number -d 'impulses of the series; after that, it automatically searches for a second selector E;

   the first selector D is switched off and the second selector E operates in a similar manner for the second series of pulses, and then automatically chooses a connector F. The .connector F. differs in its operation from the selectors in which not only responds to the third series of pulses, but also responds after the third series of pulses to the fourth series of pulses, by its rotary movement so that these rubbers are brought to the line of the desired subscriber.

   Then, the subscriber line is tested to see if it is busy or free; if it is busy, a busy signal is given to the calling subscriber; if it is not busy, the called subscriber is rung and, when he answers, the .com munication. is: established. At the end of the conversation, the connection is triggered by removing the battery from conductors 43 and 44, which allows the RRM relay to trip and open the contact 507. The RRM relay triggers shortly after, opens contact 510 and removes the setting.

         earth, contact 508.



  It is obvious that any impulse received through the conductors 43 and 44 allowed the relay LRIII to trip and establish a circuit for the switching relay CH1I, as. follows: earth, contact 506, contact 546, relay CIIi1I to [the battery.

   The CII relay <I> he </I> is energized, opens contact 51.1 and closes contact 512, thus completing a pulse circuit independent of the RTM relay. Intermittent opening of the contact <B> 507 </B> transmits the pulse to the line relay of the first selector and then to the second selector and connector. The pulse circuit can. therefore, be indicated as follows: from -from slider 549, contact 514, contact 510, contact 512, contact 507, contact 517, wiper 550.

   As is known, the line relays - successive switches D, E and F are connected by conductors whose wipers 549 and 550 are connected successively.



  Having thus studied the call from a sub-office, we will now describe the handling of a call from a subscriber-from the main office to a subscriber-from the secondary office. When a main office subscriber picks up his receiver, his SLS line switch acts to choose a free first selector such as D. Its first series of pulses causes the first selector to operate in a manner similar to that which has just been described, and the latter in turn chooses a second free selector such as E.

   The free selector E responds to the next set of pulses, in a similar fashion, but this time it is brought to a level with access to secondary office selectors such as SES (Fig. 11). When the call is sent to a secondary office selector such as SES, the LRS line relay is energized through the subscriber's wire, closes contact 521, opens contact 522.

   Closing of contact 521 completes a circuit for the PPS tripping relay. The RRS relay is energized, closes contact 524 to connect earth to test lead 551, thus maintaining switches D, E and SLS and at the same time protecting them against the intervention of other: subscribers. The RRS relay also closes contact 525 and opens contact 526.

   As we have already said, the SES switch is a one-way switch: having an active OMS magnet and an R1bZS trigger magnet. This switch is arranged to respond to 1 to 10 pulses to choose a special group of relays such as RG communicating with a secondary office. Suppose the subscriber wishes to communicate with the secondary office already described in figs. 1 to 8, that is, he chooses the long distance line <I> TL </I> including conductors 43 and 44.

   As a result, the SES relay responds to the. third series of pulses chosen on the dial and the following operations take place. When the first pulse begins, the LRS relay is de-energized and the following circuit is established: earth, contact 522, contact 525, contact 536, contact 512, active magnet OMS to the battery, while a bypass of this circuit is established as follows: earth, contact 522, contact 525, contact 536, relay <I> CILS </I> to the battery.

    The CHS relay energizes and opens contacts 527 and 529, and closes contact 528 so that a circuit can be established as follows:. From test wiper 522, contact 528, contact 541, occupancy relay BRS to the battery.

   Relay <I> CILS </I> also closes contact 532, but this has no effect at the moment. -The CIIS relay also closes contact 531: thus putting contact 536 on bypass during the series of pulses and preventing the active circuit from being opened by the excitation of the BRS relay when the wiper 552 switches to:

  contacts. After a series of pulses a. been completed and the wiper 522 is in engagement with the contact 553 connected to the test conductor 545 of the RG relay group, the relay BRS is energized if the conductor 545 is connected to earth, ie. ie if the RG relay group and the interurban line <I> TL </I> are used.

   If both are busy, the BRS relay is energized and when CHS de-energizes at the end of a pulse train, as a result of its circuit being open on contact 522, the BRS relay is blocked at the excited state in the following circuit: earth, contact 524, contact 535, contact 529 of the CHS relay, contact 541, BRS relay to the battery.

   The BRS relay closes the contact <B> 533 </B> thus transmitting the busy signal to the upper conversation conductors informing the calling subscriber that he cannot have communication with the subscriber of the secondary office that he requests. He then hangs up his receiver releasing the LRS relay which, in turn, releases the RRS relay, the two sets completing a circuit of the earth through contact 522, contact 526, normal closing contact 520, the key magnet trigger <B> RAIS </B> to the battery.

   The ISDN trigger switch is energized and returns the sub-office selector to its normal state, the BRS circuit being or green through contact 524 when the previous switch train is tripped, and the normal state of. everything is restored.

         if the interurban line <I> TL </I> is unoccupied, no earthing is established on contact 545 and, upon: return to inertia -of the CHS relay, the BRS relay being in its normal position, a circuit is established as follows:

    earth, contact 524, contact 534, lower winding of SRS switch relay, contact 527, wiper 552, test contact 553, conductor 545, contact 509, relay SRH, re <I> lais </I> SRT, contact switch 519, magnet 31LS towards the battery. In this circuit, the relay SRS, SRLII and SRT are energized. HLS ai mant does not work in this circuit, as we have already said.

   The SRT relay is energized to open contacts 518 and <B> 513, </B> -disconnecting the LRT relay. The SRNI relay is energized and opens the contacts 501 and 504, thus disconnecting the relay (the LRH line, and it closes the contacts 502 and 503 so as to connect the conductors 43 and 44 of the trunk line <I> TL </I> to conductors 554 and 555 respectively.

   The SRS relay, when energized, closes contact 540 thus completing a blocking circuit for itself as follows: earth, contact 524, cut-off 540, upper relay winding <I> SRS </I> towards the battery and at the same time it closes the contact 539, bypassing its lower winding and establishing an earth potential on the test wiper 552 and, consequently, on the -test conductor 545 - so as to protect them against the intervention of other subscribers. The SRS relay opens contact 542,

    thus preventing the subsequent action of the UMS magnet and it closes contacts 537 and 538, so that the battery is supplied by the trunk line <I> TL </I> to the secondary office selector in the following circuit:

   battery, top winding, of the BBS feedback bypass relay, contact 537, wiper 556, contact 557, .conductor 554, conductor 502, conductor 43, .contact 45, via line relay LRl, contact 46, conductor 44 , contact 503, conductor 555, contact 558, wiper 559, contact 538, contact 523, lower winding of the BBS relay to earth. The LR1 line relay at the secondary office is energized in this circuit.

   It is not necessary to give in detail the subsequent operations of LR1, since they have already been described, but we will write the transmission of the next series of pulses.



  Note that when LRS de-energizes, it opens contact 523, thus opening the loop circuit for relay LR1 as previously described, and allowing relay LR1: to de-energize and repeat the pulses <B> (the </B> the way already described. The LRS relay also completes a circuit for the CHS relay as follows: earth, contact 522, .contact 525, contact 536, CHS relay to battery.

   The CHS relay closes contact 532, thereby shorting the lower winding of the BBS relay to improve the pulse circuit; further pulses are received in the same manner as described above, and connection is established with the line of the desired subscriber. As we have already described, if the requested line is busy, a busy signal is transmitted to the interurban line, so that the calling subscriber tends the signal and hangs up his receiver.

   If the line is unoccupied, the network & the called subscriber is activated and the conversation will take place; when the conversation is finished, the subscribers, calling and called hang up their receiver. In both cases when the calling subscriber hangs up his receiver, the LRS relay de-energizes, opens contacts 521 ci <B> - </B> <B> 523. </B> By opening contact 523, it allows the LR1 relay of the secondary office @ to de-energize, but in contact 521 it opens a circuit for the RRS relay. The RRS relay de-energizes,

   opens conta. and 524 to allow selectors D and E and the SLS switch of the subscriber's line to return to the normal state, and opens the blocking circuit of the upper coil of the relay <I> SRS. </I> The SRS relay then de-energizes.

   The RRS relay also closes contact 526, thus completing a circuit for the BJIS trip magnet, from ground to contact 522, contact 526, normal or green contact 530, RMS trip magnet to battery. Trigger magnet <I> RAIS </I> then runs and returns the SES selector from the secondary office to normal state, and everything is now in normal state.



  It is understood that the installation described is susceptible to modifications: circuits as they are described and shown. For example, the arrangement described is applicable to a small, private, automatic office, and in this case the relay key groups and pulse recorders will roughly resemble the G2 relay group by removing the IS relay. . In this case, of course, it would suffice to have a single digit and therefore the test would take place during the first series of pulses, instead of waiting to start the second series of pulses.

   There would be no intercom between relay groups and the busy signal would only be given after a called line had been tried and found to be busy. It is naturally possible to have more than -two conversation circuits, for example there could be three conversation circuits having a third relay such as <B> 08. </B> This would require modifications in the intercom arrangements and would slightly increase the number of contacts on the earth line, but apart from that,

       we. will realize that it can be easily arranged by all technicians.



  Another variant might be necessary in certain cases where a second exchange line would be necessary; the drop groups would then be similar to G1 and again there would be no need to forward the call, unless there is a third talk circuit.

   It will also be understood that the installation may consist of more than ten lines, since most of the pulse transmitters are arranged for ten lines and this number is therefore the most suitable, but either a more considerable number. of lines could be made accessible to the central office with a larger capacity switch, or without increasing the capacity of the pulse transmitter, it could be arranged so that one of the relay of the.

       counter relay chain is a special relay in such a way that if the relay was chosen by transmitting a digit, it would be possible without returning to the normal state, - to receive other impulses by other counter relays above ten.

 

Claims (1)

CLAIM: Automatic telephone installation, in which the devices of the subscribers can be connected to devices controlled by current pulses by the intermediary of a line which is the first or may be the first outlet in use for the establishment. inent of a connection, characterized by a circuit serving to transmit the call of a subscriber of a device controlled by current pulses to another following the emission of a call pulse when the subscriber operates his dial, which means that the subscriber with whom a connection is desired is accessible to the second mentioned device controlled by current pulses. SUB-CLAIMS 1 Installation according to claim, characterized by a circuit (earth, 40, 78, 79, 80, 81, 82, 83, 84, 85, IS and battery, by which the second pulse device (fig. 5) ) is arranged to be used prior to the first device controlled by current pulses (Fig. 4) if said second device controlled by current pulses is unoccupied. 2 Installation according to claim and sub-rovendication 1, characterized in that the first device controlled by current pulses (Fig. 4) can control the establishment of a con nexion. With a subscriber of a distant office , while the second: device controlled by current pulses (fi ,. 5) can control the establishment of a connection with subscribers depending on the same office as the calling subscriber. Installation according to claim and sub-claims 1 and 2, characterized in that the first pulse device (fig. 4) is arranged to complete the circuit, transfer to the contact (81) of the relay (CRI.) . 1 Installation according to claim and sub-claims 1 and 2, charac terized in that the second -dispositif commanded by pulses _ (Fig. 5) is arranged to be put into operation following the transmission -d 'a number of sets of pulses when it has been busy as a result of the transmission of pulses, produced by the transmission of a call from a subscriber, and is provided. a device (SRB) by which it can, when occupied by the transfer circuit, operate as a result of a series of pulses - less than if it had been directly occupied by the transmission of pulses by the calling subscriber. 5 Installation according to claim and sub-claims 1 to 4, characterized in that the second -dispositif controlled by pulses (Fig. 5) is provided with a device (SRA) which operates when the pulse-controlled device is actuated to attempt to transmit a call to a remote control panel to cause transmission of a busy signal. 6 Installation according to claim, ca acterized in that the transfer circuit is designed to be rendered ineffective if the second device controlled by pulses is occupied and a -dispositif (FD) provided in the first -dispositif controlled by: pulses is actuated to allow said first pulse device to complete a local connection. 7 Installation according to claim, charactérized in that the first -dispositif controlled by pulses (fig. 4) is directly connected to a con- duisaut connection to a remote office, while the second: device controlled by pulses (fig. . 5) is only connected to subscriber devices dependent on the same office as the calling subscriber. 8 Installation according to claim and 1 a. sub-claim 7, characterized in that the first pulse-controlled device is arranged to be put into operation by means of said connection and is provided with a device (FRB) the operation of which allows the controlled device by: pulses, to establish a connection with one digit less than if the call is a local call. 9 Installation according to claim, .with a group of relays (SRI, SR2, SR3, SR4, SR5, SR6, SR7, SR8, SR9, SRO). Whose number corresponds to the maximum number of pulses to be recorded at the times and which are arranged so that only one relay can be actuated at a time and with a single control relay (SRB) which is arranged to change its condition after the termination of the next pulse, characterized in that the control relay is energized via a conductor to which is connected a source of excitation current between the pulses and which is worm rusted in the excited state by means of a circuit to which is connected a source of excitation current during each pulse which must be recorded. ? 0 Installation according to claim 1 and sub-claim 9, characterized in that the group of relays (SR1, SR2, SR3, SR4, 8R5, SRS, sR7, sR $, sR9, SRO) is arranged to operate as a result of a series of pulses in order to establish a momentary connection through contacts of said relays and to be actuated by another series of pulses in order to establish connections for the entire period during which the group is in function. 11 Installation according to claim and sub-claims 9 and 10, charac terized in that the relay group is arranged to record a series of pulses and to record after its return to the normal state a second series of 'pulses and then establish a conversation circuit with the line of the called subscriber through the contacts of a group relay.