Patent GB-324430-A (GB)
Title: Improvements in automatic telephone systems
IPC: H04Q3/00
Filed: 1928-11-06
Abstract: 324,430. Relay Automatic Telephone Co., Ltd., and Johnson, B. B. Nov. 6, 1928. Automatic and semi-automatic exchange systems.-In a system comprising a main exchange and a satellite exchange in which toll calls to subscribers at either exchange are set up by a main exchange operator who uses the same junctions to, and apparatus at, the satellite exchange as is used by a main exchange subscriber, the apparatus at the satellite, if taken into use by an operator, establishes a connection to a wanted subscriber either idle or busy, and withholds the usual automatic ringing. The invention is described in connection with a relay system, and the normal operation of the satellite apparatus is modified, when taken into use by an operator, by the operation of a relay MAN, Fig. 7, at a repeater at the end of a junction incoming to the satellite exchange. This results in the operation of a relav PP, Fig. 8, at a recorder at the satellite which, together with a relay PM, Fig. 18, common to a group of subscribers and over which busy battery is fed, causes a busy condition to be disregarded. The system described comprises a main exchange and a satellite exchange including junction connecting arrangements, substantially as described in Specifications 309,711 and 320,706 and the detailed description relates to the manner of setting up toll calls to subscribers at both exchanges, and automatic calls from the main to the satellite exchange. Operators' positions and circuits. Junctions aj4, Fig. 4, incoming from distant exchanges terminate at a trunk operator's position A4 from which they are extended over connecting circuits a4, b4 (all, b11, Fig. 11) to transfer circuits tj4, tp4 (tj12, tp12, Fig. 12), terminating at a connecting operator's position B4 before a multiple sj4 of main exchange subscribers' lines. Other transfer circuits tsj4, tsp4 (tsj13, tsp13, Fig. 13 at the trunk operator's position terminate at the connecting operator's position before a multiple jj4 of junctions outgoing to the satellite. Toll call to main exchange subscriber. The trunk operator connects cord circuit a11, b11, Fig. 11, between the calling junction and a idle transfer circuit, Fig. 12, thereby completing a circuit for lamp lb11 and relay 012 which lights lamps ls12, lc12 over a circuit including contacts of night alarm relay NL12. The connecting operator, seeing lc12 alight, throws key SK12, obtains the number of the wanted party, and inserts plug tp12 into the jack of the wanted line. If the wanted party is free, SLA12 operates over the sleeve to ground over his cut-off relay and extinguishes lamps ls12, lc12 whereupon the trunk operator throws key FR11 to energize B12 which operates RG12, FR12 and SLC12. in turn. When the operator restores key FR11, B12, RG12, FR12 falls back, but SLC12 remains locked over the sleeve circuit so that when ringing key RK11 is thrown, B12 and RG12 pull up and FR12 remains deenergized, the ringing circuit being completed over SLC12(2), RT12, FR12(1), RG12(2) subscriber's line, FR12(6), RG12(4). Relay RG12 locks up so that ringing continues, even if the operator restores RK11, until it is tripped by RT12. The feed relays A12, B12 pull up, and AX12 completes the connection over the awire and disconnects the key SK12. Relay A12 removes the short circuit over C12 (upper) to dim lamp lb11. At the end of conversation, A12, B12 fall back, lb11 brightens, the trunk operator withdraws, lamps ls12, lc12 light up again, and the connecting operator takes down. Wanted line busy, operator breaks in. If the line is busy as a calling party, battery is connected to the sleeve of his jack csj14, Fig. 14, (an A and B feed) over GX14(3), R14, or if busy as a called party, over GX14(4) to jack wsj14. Consequently, after the connecting operator has plugged in, and the trunk operator has thrown key FR11 to energize relays RG12, FR12, relay SLB12 operates over SLA12(2), FR12(7), RG12(6), SLC12(6), and holds over SLB12(2) to prevent operation of SLC12. Relays RG12, FR12 connect battery over RG12(4) to the a and b wires which is without effect if the line is idle. If the line is busy as a calling line, relay A1, Fig. 14, is held, but A2 falls back to release G14 and GX14 so that resistance rme is cut out of the circuit of R14 which pulls up to release ME14 which, in turn, releases R14 and the connecting relays (not shown) in the circuit H14. The established connection is thus released so that SLB12 falls back and completes the circuit of SLC12. The feed relays A12, B12 pull up immediately over the wanted subscriber's loop and AX12 operates as before. If the line is busy as a called line, B1, Fig. 14, is held and B2 releases so that G14 is released to initiate the release of the established connection as before. Call from main exchange subscriber to satellite exchange. The main exchange subscriber is connected over a junction to a repeater, Figs. 6 and 7, at the satellite, battery being connected from the main exchange A and B feed over A6, B6 and the two windings of OD6 to relay AA6 which operates G6 and GX6 in turn. OD6 being differential, does not operate. Relay G6 connects battery to conductor h7. AA6 connects battery over differential relay IS6 to a7, b7, while GX6 operates B26 and short-circuits OD6. Battery on h7 energizes relay FI, Fig. 5, at a recorder-connector which connects up an idle recorder, Figs. 8, 9, 10. This operation and the marking of the wanted line by the recorder occur as described in Specification 309,711. At the recorder, battery has been connected to the wire, drawn in thick lines, by PR8 (PF8 performs this operation if the recorder is taken for use in a local call), one of the relays of the hundreds and ten registers HD9, TN10 has been operated, and one of the relavs BK9 is released according to the value of the units digit. Relays DM(3), DG9, RH8, MC8, MCX8 have also been operated. The wanted line is marked by battery over MA8, MCX8(3), SU8, su, and through the marker to m, Fig. 18. If the line is idle, LE and D, Fig. 18, pull up, SU8 remains unenergized and the connection is completed in the usual manner. Conductor a7, a5, a8 is disconnected by the release of the recorder but b7, b5, b8 is grounded by relay RCO, Fig. 5, which has been operated to release the recorder. Consequently IS6 at the repeater is unbalanced and operates ICO7 which locks up and connects ground from b7 to short-circuit BZ6 which extends the ground to operate BB7. Relay ND7 pulls up and cuts out NU7 which has not yet operated, although its circuit has been completed. Relay RCO also connected ground to r7 to operate ringing relay RG7 which completes the ring- ing circuit over RT7. If the wanted line is busy, SU8 is unbalanced by battery on m, and at SU8(1) disconnects b8, a8 being maintained grounded at RH8(3). Relay SU8 at 4 also extends battery on the marking wire over PP8(5) to b8. Relay IS6 at the recorder is again unbalanced, but BZ6 is maintained operated by battery on b7 so that ground is connected to wire A6 over BA6(1), AA6, MAN7(3), GX6(2), ND7(5) and battery to wire B6 over MAN7(1), B26(1) and NU7(2), this relay being now operated. These conditions cause the busy signal to be given. Toll call to satellite subscriber. When the repeater is taken into use by an operator, ground on the a-wire and battery on the b-wire from the connecting circuit, Fig. 13, operate OD6, and MAN7 pulls up, locks over FR7(3) and cuts out the ringing relay RC7. The recorder is taken into use as before but an additional relay PP8 thereat operates over pp, MAN(8). The recorder is set by the connecting operator and the wanted line marked. If the line is free, relays 156 and IC07 at the repeater are operated and B26 released, as described in the preceding paragraph. Relay BB7 pulls up over ICO7(6), MAN7(9), BZ6(2) and operates ND7 so that the connection between the trunk operator and the wanted line is completed. The trunk operator throws key PR11 to connect ground over B13, B6 to short circuit AA6 which completes a series circuit for AB6 and AA13. Relay AX13 pulls up to cut out the connecting operator, and AB6 operates G6 so that FR7 pulls up over MAN(7), AB6(1), AA6(1). Relay FR7 opens the holding circuit of MAN7 but completes a further one, and also connects battery to B7 and A7, but this is without effect at present. The operator releases key FR11 so that AA6 operates again in series with BB13, and AB6, FR7, MAN7 fall back. The trunk operator throws key RK11 so that AA6 again releases to operate AB6 which completes a circuit for the ringing relay RG7, the Connection being completed in the usual manner. Satellite subscriber busy, operator breaks in. Relay SU8 operates as described in a previous paragraph, but as PP8 is operated, the wires a8, b8 remain grounded at the recorder so that IS6 at the repeater does not operate. Ground from PP8(4) over SU8(4) is now connected, in place of battery, to the marking circuit su and thence over m, Fig. 18, LE, F(5) to a relay PM common to a group of subscribers, F being operated as the subscriber is busy. Relay PM(1) completes a circuit so that one of the connecting relays LC is operated in spite of the fact that F is operated, (2) closes at PM1 a circuit for D which has been cut out by F but is required to operate to assist in completion of the connection, and (3) connects ground over PM(3) to wire s since the normal ground for this wire from contacts of LE has been removed by F. The connection is therefore completed as if the wanted party were free. The wanted line may be busy as a calling line, or as a. called line in a local or main exchange call. The Specification describes the manner in which an established main exchange call is broken down. The essential parts of the repeater over which the toll call is offered, are shown in Fig. 15, and the essential parts of the repeater in use for the established connection and of the main exchange