| 摘要 |
1. Method of connecting two-number lines to a telephone switchboard using a two-number line switchboard device containing relays detecting calls from subscribers, using the application of alternating potential to the connection line, characterized in that while a live potential is applied to one wire of the connection, the second is insulated, and in the next stroke a live potential is applied to the wire which was previously insulated, and the wire previously subject to a potential is insulated, while in order to send a blocking signal to the subscriber, a second winding of relays detecting calls from subscribers is coupled non-galvanically to wires of the two-number line switchboard device, such that each of the windings is connected to a different wire, and the blocking signal is transformed to the first windings of relays detecting calls from subscribers, the call-detection relays being supported by means of their own contacts.<IMAGE >
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