Patent GB-229765-A (GB)
Title: Improvements in or relating to automatic or semi-automatic telephone systems
IPC: H04Q3/42
Filed: 1923-11-30
Abstract: 229,765. Automatic Telephone Manufacturing Co., Ltd., and Passmore, W. O. Nov. 30, 1923. Semi-automatic exchange systems.-An operator's keyboard equipment of the register;controller type comprises two impulse-sending devices of different types, the first generating ordinary impulses in accordance with the setting of the registers when, the call is to be completed over stepby-step switches at an automatic exchange, whilst if the call is to a manual exchange the second device is brought into operation to generate code impulses for controlling a number indicator. The invention is described with reference to a system similar to that described in Specification 220,774 in which the first three digits denoting the wanted exchange are translated into the required routing digits and in the present case the setting of the exchange registers also determines whether the impulse-sending device which has generated the routing digits shall continue in operation to retransmit the numerical digits or whether it shall be replaced by the code-impulse sending device. The code employed may he that described in Specification 229,371, in which each digit comprises not more than three impulses which may differ in polarity, number, strength or order, compensating resistances being inserted in the codeimpulse circuit in the case of calls to the nearer manual exchanges. The call is established by a B-operator who assigns an idle trunk circuit 1, 2, Fig. 2, and on the depression of the assignment key 3, a switch SS1, Fig. 3, associated with the keyboard K by a pre-selecting switch OF, hunts for an idle sending-equipment, Figs. 4-6, and at the same time a call-finder TF1 hunts for the assigned trunk. When both these operations are completed, the operator sets up the number on her keyboard, the successive digits being transferred over a control switch ICS to storage-relay groups, Fig. 5. As soon as the three exchange digits are then stored, switches CS hunt for the terminals corresponding to this code and by means of the wiring at the distributing frame ISF, the switch S1S transmits first the routing digits and then either continues in operation to re-transmit the numerical digits or is replaced by the codesending switch C1S. The system also comprises means for automatically starting the transmission of impulses if a number having less than the full number of digits is set up, for routing a call to a special attendant if the exchange digits do not represent an existing exchange, for dealing with faulty and defective circuits and apparatus, and for using the trunk 1, 2 as an emergency orderwire, some of these arrangements being similar to those in Specification 220,774. Specification 214,195 also is referred to. Call to distant automatic exchange; connection of keyboard to idle sending-mechanism and operation of trunk-finder TF1. The depression of the assignment key 3 individual to the assigned trunk 1, 2, energizes relay 4 which locks up and completes circuits over conductor 19 for line relays 21, 107 of switches TF1, SS1, respectively. When wiper 68 reaches the ungrounded terminal 66, relay 25 energizes, and when the switch SS1 has also completed its operation, relay 111 operates, energizes relay 117, and extends ground over wiper 127 to operate relay 252 and over the circuit 115, 83, 66, 6, 69 to operate relay 10 which releases relay 4 and connects outgoing leads 34, 35 to wipers 73, 74. When relay 117 operates, trunkbusy lamp 65 is flickered over the circuit 12, 54, 5, 88<1>, 125, 87<1>, 77, and when relay 10 operates, a new flicker circuit 77, 55, 12, 65 is completed. Registration of wanted number. It will be assumed that the wanted number in the automatic exchange is 9013456, the first three digits of which represent the exchange code and are translated into a routing number 40. The depression of key 9 for the first digit completes circuits 163, 143, 203, 214, 301, 302, 216 and 166, 104, 33, 144, 204, 305, 216 in which relays 301. 305 energize to store the digit whilst relay 216 completes a circuit for the stepping magnet 221 of the control switch ICS, the wipers 201 - - 206 of which are advanced one step. In a similar manner the six remaining digits are stored on similar sets of storage relays 306 - - 314. At the end of the third digit which completes the exchange code, relay 232 energizes over wiper 206 and completes the parallel starting circuits 241, 369. for the stepping magnets 315 of all the code-hunting switches. When the switch shown in Fig. 5 reaches the terminals 329, 330. 331 which are connected to ground, battery and ground respectively owing to the setting of the first three storage relay groups, a consequent pole relay 316 operates to stop the switch, to connect up wipers 336, 337. 338 and to complete a circuit for relay 400 which opens the circuit of all other code-hunting switches. When the last numerical digit has been registered, wiper 206 completes a circuit 223, 225, 134, 144, 33, 104, for relay 167 which energizes stepping magnet 160 to advance the switch or to pre-select the next idle link circuit, and operates relay 151. Statistical metering. Relay 167 at armature 168 operates a meter for registering the total number of calls dealt with at the position. Transmission of impulses. When the A-operator plugs in to the assigned trunk 1, 2, relay 53 energizes and operates relay 37 which at contact 39 causes busy lamp 65 to light steadily. (If the A-operator plugs in before the B-operator has pressed the assignment key 3, the lamp is flashed over contacts 12, 54, 48.) Relay 37 also completes a starting circuit 44, 87, 154 for relay 145 which extends ground over contacts 149, 146, and lead 136. Relay 213 directly grounds conductor 135 to hold the sending mechanism busy, and energizes relay 230 which prepares a circuit 403, 420, 252, 445 for stepping magnet 431, this circuit being periodically completed at springs 420. Relays 145, 213 complete the connection from outgoing conductors 34, 35, over wipers 73, 74, leads 132, 133, and leads 249, 250 to impulse contacts 437. At the first operation of springs 420, wipers 432, 433 advance one step, relay 439 energizes over wiper 433 and removes a short-circuit 438 from across impulse contacts 437 so that succeeding operations of magnet 431 cause the transmission of impulses over conductors 34, 35. After four impulses, wiper 432 reaches the 6th contact which is grounded over the circuit 370, 346, 345, 338, 341, 413, 451 so that relay 441 energizes toopen the circuit through springs 420, to shortcircuit contacts 437 and to close a restoring circuit 433, 443 for magnet 431. Magnet 448 of control switch OCS is operated over contacts 444, 433 to advance its wipers 451 - - 454 one step. The ten impulses of the second routing digit are then transmitted in a similar manner, after which switch COS moves to its 3rd position in which magnet 448 again operates over the circuit 453, 352, 351, 336, 451 and the switch moves into its 9th position. In a similar manner, the numerical digits are re-transmitted in accordance with the setting of the storage-relay groups and the switch COS moves to its 12th position in which wiper 454 completes a circuit for relay 246. The release of relay 213 removes ground from conductor 135, unlocks the storage relays, and de-energizes relay 253 which replaces ground at contact 254 to mark the sending-equipment busy during release. The release of relav 253 also completes restoring circuits for switches ICS, OCS, and at contacts 258, 259, 260 closes other circuits to maintain relay 246 energized and thereby mark the equipment busy until its release is complete. The momentary removal of ground from conductor 135 releases relays 151, 145, 25. 10, the latter completing the talking circuit at the repeater, and connecting a momentary ground to the upper conductor to inform the A-operator that sending is completed. When the called subscriber replies, the operation of polarized relay 50 connects the coil 58 to the upper talking conductor to give the A-operator answering supervision. Call to distant manual exchange. If the wipers 333 - - 335 come to rest on terminals 354 - - 356 corresponding to an exchange code 475, two routing digits 85 are sent out in the manner already described, but in the third position of switch OCS, wiper 336 completes a circuit 451, 336, 360, 361, 362, for relays 456, 459 which both energize and insert compensating resistances 462, 463 in the code-impulse circuit, it being assumed that the manual exchange required is comparatively near and the resistance of the inter-exchange trunks is therefore a minimum. Relays 456, 459 energize relay 470 which operates relay 464 and locks up over its lower winding in series with the trunk conductors 34, 35, which are thus extended to wipers 475, 476 of the code-sending switch C1S. The transmission of code impulses which consist of combinations of two or three impulses varying in order, strength or polarity, takes place in the manner described in Specification 229,371, and is commenced by the release of relay 470 when the distant apparatus is ready to receive the coded number. After the last coded digit has been sent, wiper 477 in its 19th position completes a circuit in series with stepping magnet 483 for a low-resistance relay 478 which grounds lead 455 to operate relay 246 and the sending-mechanism is released as before. Starting transmission of impulses if total number of digits is less than the normal, e.g. for call to complaint or information operator. If, after the third digit has been stored, relay 222 remains de-energized owing to no further storage of digits, slow interrupter 245 operates relav 238 at first partially and then fully, so that when the interrupter next connects up ground, this ground is extended to lead 134 to start the transmission of impulses as before. If the operator presses another assignment key before