Patent GB-530614-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04M15/08
Filed: 1939-05-11
Abstract: 530,614. Automatic exchange systems. POLLAK, J. E. (Associated Telephone & Telegraph Co.). May 11, 1939, No. 15445/40. Divided out of 530,443. [Class 40 (iv)] In a system for identifying a calling line for ticketing, cross-bar switches are used, the identification being effected by successive operation of appropriate combinations of the vertical and horizontal magnets to determine the group and sub-group to which the line belongs and then testing for the line itself. Two arrangements are described. First arrangement. Figs. 1 ... 3. The testing unit for a 10,000 line exchange comprises five 200-point cross-bar switches of which each point has ten contact pairs, each pair being individual to a line. When a converter is seized, the start relay 1340 in the identifying circuit is energized and the converter is marked in the banks of switch F which then operates finder fashion, provided the identifying circuit is in its normal condition. When the converter is reached, 1330 pulls up and magnet 1371 of distributer switch 3S is energized and a self interrupting circuit is made for impulse-generating relay 1320 to drive the thousands register 3M which in successive positions operates relays 1M, 2M &c. of which there are two for each cross-bar switch. 1M energizes the top five horizontal magnets and, with the aid of EC, OC, the twenty vertical magnets and so on. When the calling thousands group is reached however an A. C. circuit is completed from transformer 1335 the primary of which carries 2000-cycle current over the C-wire of the established connection, the individual wire 254, one of the operated spring sets (shown enlarged at the bottom left hand corner of Fig. 1) and wire 1113. Relay 1300 in the anode circuit of a valve 1302 responds, energizes 1310 which stops the impulsing relay 1320 and releases magnet 1371 to allow the distributer switch 3S to make its step and apply a marking ground over wipers 1355, 1356 of the thousands register to appropriate relays of the W, X, Y, Z register in the converter. Switch 3S also energizes MS which transfers the circuits of the horizontal magnets and relays EC, OC via cable 1101 to the upper wipers of the hundreds register 2C. These magnets and relays and also relays 1300, 1310 then fall and the impulse-generating relay 1320 is re-started. This time the hundreds register is stepped and in successive positions energizes one horizontal and ten vertical magnets. This operation is stopped as before by 1300 which energizes CS when the hundreds group has been identified and 3S is stepped on causing the record of the hundreds register to be transferred to the converter. The operated horizontal magnet is held over the register 2C but the ten vertical magnets of the selected group which were released by CS are now energized in succession by the tens register until the operation is stopped by 1300 which energizes DS. The record is then transferred and the individual wires in cable 1011 are tested by 2U to ascertain the units digit. The final operation of 1310 causes the transfer of the units digit after which relays 1340, 1330 are released and are followed by all the operated relays in the identifying arrangement, the switches of which go home. The transfer of the identifying circuit to the converter may be withheld unless the identifying circuits give the same record as described below. Second arrangement, Figs. 4 .... 6. In this system the cross-bar switches are used as before and the general operation is similar but the rotary switches are replaced by relay groups. The operation of 1330 energizes MK which connects the armatures of counting relays 1R to 10R to relays 18M to 10SM of the thousands register. The first impulse from 1320 energizes 1R which locks in series with RA which diverts the second impulse to 2R which locks in series with RB dropping 1R and RA. The third impulse thus goes to 3R which locks in series with RC dropping 2R and RB. 4R locks in series with RA again and so on. 1R energizes 1SM which energizes 1M, Fig. 1 to test the first thousands group. Similarly 2R energizes 2SM and so on. When the A.C. circuit is completed and 1300 pulls up 1310 disconnects 1320 and releases the counting relays, the operated one of the register relays 1SM .... 10SM, remaining locked in series with ML and holding the corresponding relay 1M ... 10M. Relay ML also energizes MS, drops MK and energizes CK. The counting relays are then operated again and control relays 1SC .... 10SC and then 1SD .... 10SD and 1SU .... 10SU for the hundreds tens and units digits. In this arrangement two detectors are operated simultaneously to ascertain the number and when UL operates on the completion of the test a circuit is made for 1360 through contacts of all the registers in both detectors, if the detector-settings agree, to prevent the operation of a sluggish relay 1350 which otherwise gives a fault alarm, to transfer the setting of the detector registers to the converter registers and to initiate the transfer of this setting to the toll line control circuit and the release of the identifying circuit.