Patent GB-703223-A (GB)
Title: Improvements in telecommunication switching systems
IPC: H04Q3/42
Filed: 1952-06-30
Abstract: 703,223. Automatic exchange, systems. COMPAGNIE INDUSTRIELLE DES TELEPHONES. June 30, 1952 [July 5, 1951], No. 16399/52. Class 40 (4) In an automatic exchange system of the type described in Specification 668,261 in which batteries individual to the registers are used to test over a common marking multiple, arrangements are made to control the marking wire circuits so that if desired first group selector outlets in a particular direction are accessible only to a particular group of incoming lines. As shown the group of incoming lines, comprise a group of jacks in an operator's position, and a key 823 associated with the said group, when thrown, operates relay 420. With the key unoperated the system works in the normal manner, but when the key is thrown relay 420 disconnects the marking wire 2 associated with a given outgoing direction so that incoming lines belonging to other groups cannot obtain access to outgoing lines in that direction. For incoming lines of the group associated with the key 823 however, the marking wire 2 is connected via the line finder wiper 807 to the register to complete the marking circuit. Detailed operation. Normal operation with key 823 unoperated. When the operator plugs in relay 410 operates over the tip and brings up 600 and 620 in the register. The latter energizes the link finder magnet 900 and when the link CC having access to the calling line is found relay 620 releases by differential action and stops the link finder. Relay 620 brings up 550 which inserts the resistance 931 in the circuit of the upper winding of 620 which being thus unbalanced reoperates and is followed by 540 which releases 550. The latter energizes the power magnet 819 of the line finder which rotates until the calling line is found whereupon 520 operates to stop the switch. Relay 520 brings up 530 which releases 520 and brings up relay 400 associated with the jack. The last is connected in series with the upper winding of 620 which releases differentially. Relay 400 releases 410. Relay 520 releases 530. Relay 620 brings up 570 followed by 560. Relays 600 and 540 release. Relay 570 brings up 610 and 620 the former causing the switch 920 to stop. As relay 420 is unoperated a test circuit is completed over wiper 922, wire 5, wiper 806 of the line finder and wiper 813 of the link finder to operate 630 which stops the switch 920. Dial tone is sent and dialled digits are received in the usual way to set the digit switch 930. Relay 640 operates to energize 500 over wiper 924 and 610 releases followed by 640. Relay 610 brings up 580 which energizes the power magnet 820 for the first group selector. With the marked contact of the digit switch connected to the marking wire 2 by contact 422 (back) the selector rotates until the marked wire 2 is encountered whereupon 630 is operated by the individual battery and stops the selector. Operation with key 823 thrown. Relay 420 operates and disconnects the marking wire 2 from the digit switch so that selector outlets characterized. by this marking wire are not normally accessible to incoming lines. In the case of incoming lines associated with relay 420 however, when the switch 920 hunts it stops when its wiper 922 is connected to lead 4. When the relay 640 is now brought up by test relay 630, relay 510 operates over wiper 924, disconnects wiper 930 of the digit switch and connects the test relay to wiper 812 of the link finder. Relay 510 brings up 500 and 640 releases 610 and 630. Relays 640 and 620 release and 610 reoperates followed by 580, 590, 620. The selector magnet 820 is then operated and the selector stops when the test relay 630 operates in a marking circuit passing over wiper 812 of the link finder, wiper 807 of the line finder and marking wire 2. If a calling line belongs to a group having no key 823 or relay 420 the switch 920 steps to its last position where it is stopped by the operation of 630 over wiper 922. Relay 500 then operates over wiper 924 and the selector is caused to hunt as previously described.