Patent GB-227824-A (GB)
Title: Improvements in or relating to telephone systems
IPC: H04Q3/00
Filed: 1925-01-08
Abstract: 227,824. Western Electric Co., Ltd., (Assignees of Carpenter, W. W.). Jan. 19, 1924, [Convention date]. Automatic exchange systems.- In a system in which dialled numbers are received by impulse recorders and afterwards transferred to markers, and in which calling lines are extended over non- numerical switching mechanisms to any of a number of group-selector switches arranged in groups, means are provided for connecting simultaneously a plurality of markers to the selector switches in such a way that each controls the particular switch to which the corresponding calling line has become connected. The arrangements for transferring the dialled number from the recorder to the marker are such that the operation is unable to proceed further if the transfer circuits are defective. In the system shown, a calling line 101, Fig. 1, is extended over a non-numerical cross-bar switch 100 to a trunk 104 leading to a cross-bar group selector 200, Fig. 2, and over a second non-numerical cross-bar switch 110 to an impulse recorder, Fig. 3, which is associated over multi-contact relays 320 with a marker (shown on the left of Fig. 4). The arrangements for associating the marker with the proper group selector 200 comprise multi-contact relay sets 425, 426, one set to each group of selectors, the selection of the proper group being controlled by a combination of low and high resistances 112, 113, Fig. 1, particular to lines in that group, which resistances cause the selective operation of a set of relays 419 - - 423 in the marker and result in the operation of relays 430 - - 432. The connection of the marker to the particular switch 200 in the selected group is effected by a relay 427 individual to that switch. The arrangements for checking the transfer of the dialled number from the relay registers 305 - - 307 of the recorder to the corresponding relays 400 - - 402 of the marker comprise means for first operating all the relays of the groups 400 - - 402 and then maintaining operated only those which correspond to the operated relays of the recorder, the operation of all the relays normally completing a chain circuit, the non-completion of which in the event of any circuit being defective, prevents the establishment of a wrong connection. Checking transfer of number from recorder to marker. A calling subscriber 101 having been connected to a selector trunk 104 and to an impulse recorder, Fig. 3, a circuit is completed at the latter for relav 106 which operates relay 108 and extends the calling loop over leads 120. 121 to impulse relay 300 and coil 301, the three digits of the wanted number being repeated by relay 300 to the relay registers 305 - - 307. The relay device 320 is now operated to connect the recorder to a marker at which a relay 424 is operated to ground lead 435 and to operate a relay 417. Circuits are completed by relay 417 for relays 321, 322, 323, which in turn complete circuits for all of the relays of the sets 400 - - 402. If all the contacts of the device 320 are operative, the relays 400 - - 402 complete a chain circuit for a relay 416, which in turn operates relay 415 to break the circuit of relays 321 - - 323. The only relays of the sets 400 - - 402 which now remain operated will be those which correspond to the operated relays of the recorder 305 - - 307. Associating marker with group selector 200. Each of the trunks 104 leading to selectors in the group containing the selector 200 has associated therewith low and high resistances 112, 113, respectively, the trunks in other groups having resistances arranged in different combinations. In the present case, when the recorder has been connected to the marker, circuits 112. 124, 341, 422, 419, 435 and 113, 123, 340, 423, 420, 435 are completed in which relays 419, 420, 422, but not marginal relay 423, energize and a circuit from lead 435 is completed for a relay 432 which in turn causes the operation of relays 431, 433, 430, the latter associating the marker with the relay set 425 individual to the group containing the selector 200. The connection of the recorder to the marker also resulted in the completion of a circuit over lead 342, extending back over the switch 110 to the in-marking magnet 218, Fig. 2. which magnet operates to close a circuit for a relay 427 to complete the association of the marker with the particular selector 200 in use. When the controlling operations have been completed, the link-operating magnet 227 remains locked over lead 125 to maintain the connection, and upon the release of the recorder and marker, relay 106 relapses to complete the talking circuit and supervisory relay 107 operates to hold up relay 108 and the operated switches. Specification 222,502 is referred to.