Patent GB-212666-A (GB)
Abstract: 212,666. Automatic Telephone Manufacturing Co., Ltd., and Gillings, C. Dec. 19, 1922. Addition to 193,694. Automatic exchange systems.-A register-controller particularly for use in a system of the type described in Specification 194,580 in which the register-controllers are divided into groups, the groups taken into use being determined by the first digit of the exchange code, is modified to comprise the following features.-(1) If an unusually-long pause occurs between the dialling of the first and second or between the second and third exchange digits, a timing-device causes the closure of the starting-circuit for the re-transmission of impulses, and also modifies the setting of the register-controller so that the calling subscriber is connected over group selectors to a special operator's position. If the pause occurs after the third digit, the same timing-device operates, as in the above-mentioned Specification, to release the register-controller and put the numerical switches at the wanted exchange directly under the control of the calling subscriber. If a delay occurs in the re-transmission of impulses from the register-controller, the timing-device operates an alarm to attract the notice of an attendant. (2) Whilst the register controller is arranged to deal normally with numbers having four numerical digits, in the case of calls to smaller exchanges having only 1000 or 100 subscribers, the registercontroller releases itself and switches the calling subscriber through, immediately after re-transmitting the necessary two or three numerical digits and without waiting for further dialling. (3) Local lines, for example in a branch exchange, may be wired to certain levels of the first group selectors, and the dialling of the local exchange code causes the whole code to be suppressed, the first group selector and succeeding local switches being operated by the numerical digits, either directly from the calling subscriber or after retransmission by the register-controller. (4) In some cases, for example, for calls to exchanges containing a manual position without call indicators, the re-transmission of impulses does not commence until the whole set of code and numerical digits have been stored at the register-controller. In the system described, the registercontroller, Figs. 2-5, corresponds to that shown in Figs. 2-5 of Specification 194,580, and in the following more detailed description of the modifications, it will be assumed that normally this register-controller is taken into use by the first exchange digit dialled and that the wipers 306 - - 309 of the switch J are moved on to a set of terminals 500, &c. in response to the remaining two exchange digits, the switch M advancing its wipers 218, 219 one step at the end of each digit. Delay in dialling digits. Relay 210 is operated over the ground lead 203, 102, and every 30 seconds the cam T grounds conductor 299, partially operating relay 206 which connects up its lower armature 522. As soon as ground is removed from conductor 299, relay 206 fully operates over both its windings in series with grounded armature 215. If the code impulses arrive at their normal rate, the operation of relay 207 during any digit, de-energizes relay 206. If, however, a long pause occurs after the first or second exchange digits, relay 206 remains energized and the next grounding of conductor 299 completes the circuit of the upper winding of relay 205 whilst the lower winding is connected over contact 523 and conductor 524 to the grounded wiper 219 in its first or second position. Relay 205 thus energizes, locks up and connects grounded lead 524 to starting conductor 400 to initiate the generation of impulses by the switch S. Conductors 411 - - 414, extending from the bank of wiper 404 of switch S<1> to the wipers 306 - - 309 which in this case have not been rotated on to any contacts, are connected by relay 205 over conductors 532 - - 529 to terminals 342 - - 345 and thence across the distributing frame IDF to terminals which result in the sending out of the necessary impulses for routing the call to an operator. When switch S<1> reaches its fourth position, switching relay 112 (which is made slightly slow to energize to prevent it energizing over contacts 525 before relay 205 operates) energizes over the circuit 420, 406, 373, 345, 529, 414, 404, 511, 400, 527, 219 and releases the register-controller. If a pause occurs after the third exchange digit, relay 205 is not operated and relay 206 completes a circuit 299, 54, 525, 201 for switching relay 112 which releases the register-controller and transfers the control of the numerical switches directly to the calling subscriber. Operation if no impulses re-transmitted from the register-controller within a given time. A relay 551 connected to the timing device T in a similar manner to relay 206, operates partly over its lower winding and closes its contact 554, thus connecting its upper winding over the circuit 556, 557, 558, 511, 400. If impulses are being sent out by switch S, relay 106 will open this circuit and relay 551 will release. If, however, no impulses are sent out, relay 551 will operate fully over both its windings when conductor 299 is next grounded. Relay 559 will thus energize over armature 553 and lock up over attendant's key 560 to operate an alarm 563. Calls to exchanges having 2- or 3-digit numbers. The lower terminal of a set of terminals 500 corresponding to an exchange having 3-digit numbers, is connected to a relay 513 which operates over wiper 306 and circuit 411, 404, 511, 400, 219, and, at armature 515, connects ground to the 8th contact in the bank of wiper 406 so that after the transmission of the third set of numerical impulses relay 112 operates over wiper 406 and releases the register-controller. In a similar manner, a relay 518, connected to a terminal 502 corresponding to a 2-digit exchange, connects ground to wiper 406 in the 7th position of switch S<1>. Local call; cancelling exchange code. In a branch exchange of 900 subscribers, all calls to other exchanges are routed bv the register-controller over the tenth level of the first group selectors, local calls being completed over the first nine levels which lead to local connectors. The dialling of the local-exchange designation brings wipers 306 - - 309 on to a set of terminals 504, the lowest of which is connected over conductors 539, 420 to switching relay 112 which operates to release the register-controller immediately so that the local switches are placed under the direct control of the calling subscriber. If it is desired that the numerical impulses should be stored and retransmitted by the register-controller, the lowest terminal of the local-exchange terminals, for example, terminals 505, is connected to a relay 540 which disconnects ground from armature 133-, connects ground over conductor 544 to drive switch S<1> into its 2nd position, and disconnects relay 111. The latter, in falling back, connects ground to the 2nd, 3rd and 4th terminals in the bank of wiper 403, thus causing switch S<1> to move into its 5th position in which the re-transmission of the numerical impulses is commenced in the usual way. Delaying the re-transmission of impulses until the whole code and numerical designation has been dialled. The lowest terminal 506 of the set of terminals corresponding to an exchange in which such delay is required, is connected to a relay 508 which transfers the connection of the starting lead 511 from conductor 400 which is grounded in the 3rd position of switch M to conductor 550 which is only grounded when the last numerical digit has been recorded on register M<4>. A sluggish relay 510, energized over wiper 219 in its 1st and 2nd positions, ensures circuit 511 remaining open until relay 508 has had time to operate.