Patent GB-301828-A (GB)
IPC: H04Q5/22
Filed: 1928-11-28
Abstract: 301,828. Siemens & Halske Akt,.- Ges. Dec. 6, 1927, [Convention date]. Automatic exchange party-line systems.- In a party-line system in which the selection of the wanted party is effected by impulses transmitted over the line. each impulse extending the line from one station to the next, the building up of the line to the exchange in the case of an outgoing call takes place automatically in response to the subscribers' calling signal. In the system shown, calls to the party-line, Fig. 2. are made over a connector, Fig. 1, having a different set of terminals for each party on the line, the impulses necessary for selecting the wanted station being transmitted automatically under the control of a switch DA which hunts for the connector terminals over which the call has arrived. Call to party-line subscriber Tn2 ; setting of connector. Fig. 1. When the connector is seized, relay V1 operates over wiper c1 and energizes relay F which causes magnet St to move the sequence switch to position 2, relay F being released by a short-circuiting contact 2st. The impulses of the first digit are repeated by relay A1 to vertical magnet H and at the end of the digit the relapse of relay V2 energizes relay F over vertical off-normal contacts 4k whereby the sequence switch moves to position 3. The second digit similarly passes to the rotary magnet Dafter which relay F operates over rotary off-normal contacts 5w moving the sequence switch to position 4 from which it automatically passes to position 5. If the wanted line is free, relay P operates over lead c2, contacts 38sp (relay Sp being normally energized over the charging circuit referred to below) and relay C, and moves the sequence switch to position 6. Selection of wanted station. Relay C energizes the lower winding of relay V4 which releases relay Sp so that relay J energizes and completes a circuit for the stepping magnet Dn. The re-operation of relay Sp over magnet contacts 29 da releases J and the magnet. Relay J then re-operates and stepping of the switch continues until wiper da1 reaches the terminal (in this else, the second), over which the call has been received when relay P1 operates and disconnects @. The first release of relay J completes a circuit over contacts 88i, 85c, for relay X which operates relay C1 so that on the re-energization of J, the release of X causes the operation of relay U1 over contacts 93f1, 106x, 105c1, 81c, 83p1, 32v4. Relay U1 energizes relay F1 which completes the bwire through the station of subscriber Tn1 so that at the next release of relay J relays X1, C2, operate. Since relay P1 has now operated the circuit for relay U2 (corresponding to that traced above for U1) is not completed but relay P3 operates connecting up the subscriber's instruments. Ringing. The operation of relay V5 over its lower winding connects ringing current over relay U, contacts 70sp, 82p1, 81c, 115p3, subscriber Tn2. relay U2 and contacts 113f2. When the called subscriber replies, relay U2 operates and energizes F2 which switches through. Relay U also operates, connecting relay A3 in a circuit 86u, 85c, U1 U2, Tn2, 81c, 82p1, 70sp, 60u. 49v5, 32v4. Relay A3 completes a circuit for the upper winding of relay F, Fig. 1, which drives the sequence switch to its 7th (talking) position. Relays A2. V3 also operate. Release. When the called party hangs up, relays U1. U2, F1, F2, P3, A3, A2, release followed by relay V3 which causes the connector sequence switch to move into position 8. When the calling party hangs up, relays A1, V1, V2, release. completing a circuit for the release of magnet M and closing a short-circuit around relay P which in turn releases relays P1, C, V4. When the connector preaches normal, the closing of contact 8k moves the sequence switch to position 1. Switch DA returns to normal over wiper da2 and inter-' rupter RU. Outgoing call. If subscriber Tn2 wishes to make a call, he depresses key tal energizing relay D3 which connects the substation set Tn2 in a circuit 113f2, U2, 104c1, 80c, 33v4, Sp. Relay U2 oparates and connects up relay F2 which extends the b-wire to station Tn1 at which relay U1 similarly energizes and further extends the b-wire to relay A3 at the exchange. Relay A3 completes a loop for a line switch VW and the connection is completed in known manner. In a modified circuit arrangement, the relays U1, U2, have an extra winding in the a-wire so that these relays all energize simultaneously when an outgoing call is initiated. Substation battery charging. When the partyline is idle, small-voltage batteries at the substations are charged over a circuit including the a-wire, contacts 80c, 33v4, and relay Sp.