Patent GB-181119-A (GB)
Abstract: 181,119. Relay Automatic Telephone Co., Ltd., Ward, F. M., and Johnson, B. B. March 7, 1921. Automatic and semi-automatic exchange systems.-An impulse responding and recording device can so modify its condition as to require for its operative setting a variable number of digits. This modification is brought about either by its response to one or more predetermined digits or by reason of the calls being made over different types of connection, for example, calls from local subscribers and calls from distant exchanges. The invention is described with reference to a relay selector of the type which, in response to dialing impulses, establishes a temporary marking circuit particular to a wanted local subscriber or to a group of exchange trunks, which selective circuit is released when a talking connection has been extended over another path by a relay connecting organization. The two methods of varying the digital capacity of the relav selector are described with reference to Figs. 1<a>, 1<b>, 1<c> and Figs. 2<a>, 2<b>, 2<c> respectively, which should be arranged, Fig. 1<c> above Figs. 1<a> and 1<b>, and Fig. 2<c> above Figs. 2a and 2<b>. First method : general operation. In the modification shown in Figs. 1<a>, 1<b>, and 1<c>, the relay selector normally responds to three digits, the first operating a hundreds relay HD, Fig. 1<b>, the second a tens relay TN, and the third completing a marking circuit on a units wire U, marking circuits at the same time being completed on a hundreds wire H and a tens wire T. If, however, the first digit is 8 the digital capacity of the selector is increased to four digits, since the operation of the hundreds relay HD3-8 in response to eight impulses completes a circuit 17 for an auxiliary controlling relay DMX, which causes the second series of impulses to operate an auxiliary hundreds relay HDX. The third digit causes the energization of a tens relay TN, whilst the fourth marks a units wire U and completes marking circuits over an auxiliary hundreds wire HX and a tens wire T. Connection to and preparation of an idle relay selector. A calling party having gained access to a connecting apparatus, Fig. 3, in known manner, negative potential is applied to the wires A, B, H (indicated in the top right-hand corner of Fig. 3). A relay F<1> energizes in a circuit 4, locks up over a simplex circuit 4a, and completes circuits 5, 5a, 5b through the connecting relays RC<1>, RC<2>, RC<3> and preparing relays, as P, Fig. 1<c>, of the associated idle selectors. Where the associated selector is busy, this circuit will be broken at the contact of the busy relay BY. Assuming, however, that the selector shown in Figs. 1<a>, 1<b>, and 1<c> is idle, the relavs P and RC<1> energize in the circuit 5, the relay RC<1> disconnecting circuits 4, 5a, 5b. The energization of relay P completes the circuits 8, 9, 10. Relays RSR<1>, RSR<2> operate in circuit 8 and lock up, all the break relays BK of the responding apparatus, Fig. 1<a>, are energized in parallel over back contacts of the relays MK in a circuit 9, and the hundreds controlling relay DM<1> responds in circuit 10. The first make relay MK<1> is thereby energized over circuit 11, locks up over a contact of the relay BK<2> and de-energizes the relay BK<1>. The selector is now ready for the reception of impulses. Setting of the selector by a three-figure number. Assuming a subscriber 911 is to be called, when the calling party proceeds to dial the figure 9, at the first break negative potential is removed from the wires A, B, Fig. 3, and the relay F<1> de-energizes, thus extending the calling line to the relay selector, and completing a holding circuit 12 for the relays RC<1> and P in which the busy relay BY also responds. The second impulse passes over the impulse wires A, B, and energizes the second make relay MK<2> in circuit 6', this relay holding in a circuit 13 in which the relay DC<2> is also energized. The relay DC<2> completes a circuit for the relay DC' which is slow acting, however, and only energizes during the prolonged make between digits. On the cessation of the second impulse, the second break relay BK<2> relapses, breaking the locking circuit of relay MK<1>, and thereby allowing the relay BK<1> to be energized again in the circuit 9. Similarly the third impulse energizes the relay MK<3>, whilst the third break de-energizes the relays BK<3>, MK<2> and re-energizes the relay BK<2>. This cycle is continued, a relay BK de-energizing at each break and preparing a circuit over one of the wires leading from the right-hand side of Fig. 1<a>. At the cessation of the sixth impulse the relay BK<6> relapses and completes a circuit 14 for a hundreds differentiating-relay HD6.<c> which locks up over contact 14<1>. The ninth break causes the de-energization of the relay BK<9>, whilst the make following it energizes the relay MK<0> and being prolonged during the re-setting of the impulse transmitter allows time for the response of the relay DC<1>, which completes a circuit 16 for the hundreds relay HD4.9. A marking circuit is thereby prepared over the hundreds wire 31. It will be seen from an inspection of the drawing that two marking wires lead to each hundreds relay HD, d serimination being effected by the relay HD6.<c>, which is energized when digits 6 to 9 and 0 are dialled. The marking wires HX and T are similarly arranged with respect to the relays HDX and TN. Relav HD4.9 locks up and breaks the circuits of relays DM<1>, MK<9>, MK<0>, DC<2>, DC<1>, the release of relay MK<9> permitting relay BK<9> to energize again. All the break relays BK are now energized and a circuit 20 is completed for the tens controlling relay DM<2>, which closes a circuit for the make relay MK<1>. The selector is now ready to receive the second series of impulses which in the manner already described cause the impulse responder, Fig. 1<a>, to complete a circuit for the tens relay TN1.6, which locks up. prepares a marking circuit 25 over a tens wire T, and de-energizes relays DM<2>, MK<1>, MK<2>, DC<2>, DC<1>. The units controlling relay DM<3> is now energized in circuit 22, and the impulse responder is again set ready for the reception of the units impulses. The first break de-energizes relay BK<1> as before, and the final closure of the loop across the calling line energizes the relays MK<2>, DC<2>, DC<1>. The relapse of relay BK<1> prepares a circuit 30 over a units marking wire U, whilst the relay DC' completes a circuit 24 for the marking control relay MC, Fig. 1<c>, which energizes the hundreds and tens marking circuits 31, 25, shortcircuits relay RSR', thereby de-energizing relay RSR<2>, and closes a circuit 27 to operate a meter. Relay MCX energizes in circuit 25, completing the units marking circuit 30, and a circuit 29 which energizes a marking relay in the relay connecting organization (relay OTM<1>, Fig. 2, Specification 181,120). When the relay connector has established connection with the wanted line, the relay RCO, Fig. 3, is energized and breaks circuit 12, thereby de-energizing relays RC<1>, BY and P, and bringing about the release of all the relays in the selector. Setting of the selector by a four-figure number. For this the first digit must be 8. The selector responds to these impulses as described in the previous paragraph, the hundreds relays HD6.<c> and HD3.8 energizing in circuits 14 and 16 respectively. By the conjoint operation of these two relays a circuit 17 is completed for the auxiliary relay DMX, which causes the second series of impulses to be effective to operate an auxiliary hundreds relay HDX, and prepare a circuit for an auxiliary hundreds marking wire HX. The third and fourth digits prepare marking circuits over a tens wire T and units wire U respectively, these and subsequent operations being the same as described in the previous paragraph. Response of selector to one digit. The wanted line may be characterized by its group, the choice of a particular line being left to apparatus such as described in Specification 181,120. Such a connection may be obtained when the digit O is dialled, the point g, Fig. 1<b>, being connected to the point j instead of k, so that after the first digit is dialled a circuit 32 is completed to energize a relay MX, Fig. 1<c>. Circuits 33, 33a are thereby completed for relays MC, MCX, and marking circuits 29, 34 are energized to effect immediate connection to the wanted exchange. Second method : general operation. In the modification shown in Figs. 2<a>, 2<b>, and 2<c>, the relay selector is adapted to vary its digital capacity according to the type of circuit requiring its services. It is provided with two preparing relays P. PR, Fig. 2<c>, which are respectively energized when the selector is engaged by a local line and a distant exchange line. Both local lines and distant exchange lines are allotted four-figure numbers. If the selector is engaged by a local line, the energization of the preparing relay P completes a circuit 35 for the relay DMM, Fig. 2<b>. If connection is required to another local line the operation of the responder, Fig. 2<a>, by the first digit 3, which is a predetermined digit allotted to local lines, will cause the energization of a relay TH in circuit 36. The relay TH then releases the impulse responder, Fig. 2a, and de-energizes the relay DMM, thus absorbing the first digit. Subsequent series of impulses mark a hundreds, tens and units wire. On the other hand, if connection is required with a distant exchange, the first digit 9, allocated to the distant exchange, will cause the response of a relay MX, Fig. 2<c>, in the manner described in the previous paragraph, and immediate connection will be obtained to the wanted exchange, where the three remaining digits will be effective. If the selector is engaged by an exchange line, the preparing relay PR, Fig. 2<c>, is energized and the controlling relay DMM in this case