Patent GB-195356-A (GB)
Abstract: 195,356. Relay Automatic Telephone Co., Ltd., (Assignees of Betulander, G. A.). March 22, 1922, [Convention date]. Automatic exchange systems.-In systems in which an incoming line 1L, Fig. 2, is connected to an idle outgoing line UL selected by a non- numerical selector or " searcher," the marking of the incoming lines in the cross-bar or other connecting-apparatus AK is controlled by the searchers S1, S2, of which there are several in each switching division, so that an incoming line will be marked only in the connecting-apparatus associated with the outgoing line selected by the searcher. When there are simultaneous calls, the lines to be connected will be marked simultaneously and separately in different connecting- apparatus. Similar arrangements may be used at a group-selecting stage. General arrangement. Each searcher controls a separate group of marking circuits MS1, MS2 by means of relays GR1, GR2 through which each group can be switched on to any connecting-apparatus. Each group of marking circuits is controlled by. a callsequence controller OK1, OK2 consisting of relays which prevent a simultaneous marking of more than one line in each group of marking wires. The searchers may select the outgoing lines in a different order of sequence, and the incoming lines may be divided into groups G1, G2 each provided with a separate searcher S1, S2. Circuit connections. Figs. 4, 4<A>, 5 show two groups G1, G2 of incoming lines divided into sub-groups UG1, UG2, the line 1L1 being represented by its line and cut-off relays LR1, UR1, and other lines by their line relays LR2, LR3, &c. The outgoing trunk UL1 is multipled to all the terminals of the cross-bar selector AK1. represented by the contacts KG and magnets AR1, AR2, AR3, and MR1 - - MR4. A second outgoing trunk UL2 is similar. The searchers S1, S2 are accessible from the groups of incoming lines G1, G2 respectively, but have common access to all the outgoing trunks. When a call occurs on line 1L1, its line relay LR1 closes a circuit 2 for a relay BR1, associated with the sub-group UG1. Relay BR1 locks up over circuit 3 in series with a common relay DR1, which opens the energizing circuits of all relays BR1, BR2 &c. of group G1. Relay BR1 also energizes over circuit 4 a relay CR1, associated, say, with the first lines in each sub-group. Relay CR1 locks up over circuit 5 in series with a common relay ER1 which opens the energizing circuits of all relays CR1, CR2 &c. in group G1. Thus only one of the relays BR1 &c. and one of the relays CR1 &c. can be energized at a time, thereby preventing confusion by simultaneous calls in the group G1. The relays BR1, CR1 earth marking wires which are subsequently connected to the cross-bar selector individual to the selected outgoing trunk. The relay DR1 closes a circuit 6, which, if the first outgoing trunk UL1 is free, includes relay SRI which locks up over a circuit 7, including a relay G1R1 individual to the outgoing trunk. The relay G1R1 locks up in series with a common relay HR1, which by opening circuit 7 prevents disturbance by calls from group G2 and searcher S2. If the relays G1R1, G1R2 are energized simultaneously by calls from searchers S1, S2, relay G1R2 opens the circuit of relay G1R1, thus preventing the same trunk being seized from both groups Gl, G2. Relay G1R1 connects the marking circuits MS1 to the magnets of the connecting- apparatus AK1 individual to the selected trunk UL1, magnet MR1 being energized over circuit 8 and completing a circuit 9 for magnet AR3. The magnets MR1, AR3 jointly close contacts EG1, whereby the incoming line 1L1 is extended to the outgoing line UL1, a circuit 10 being completed through the holding-winding of the magnet AR3 and the subscriber's cut-off relay UR1. Relays LR1, BR1, GRI &c. de-energize, the connections being maintamed by magnet AR3. which closes a circuit 11 for a relay FR1, whereby the trunk UL1 is marked busy. Reference has been directed by the Comptroller to Specifications 192,712 and 193,049.