| 摘要 |
PURPOSE:To enable to use the same telephone set as generic subscribers and to eliminate the need for attendant boards, by providing an incoming/outgoing call discriminating means between a number of common telephone sets and subscriber terminals of an exchanger. CONSTITUTION:A number of common telephone incoming/outgoing call discriminator 4 is provided between common telephone sets 11, 1n and a subscriber terminal 3 of an exchanger 2. The call of the telephone set 11 is detected at an outgoing call discriminator circuit 6, a connecting circuit 7 is started from a control circuit 5 and a channel to the subscriber terminal 3 is set. The information discriminating the outgoing common telephone set 11 is transmitted to the exchanger 2 via the circuit 6. In case of incoming call, an incoming discriminating circuit 8 can discriminate the common telephone set 1n, and the control circuit 5 starts the circuit 7 to set the channel for the telephone set 1n and the subscriber terminal 3. |
