| 摘要 |
PURPOSE:To make unnecessary the special common battery trunk which identifies the outgoing of the special common battery subscriber and to simplify the private branch of exchange, by identifying the outgoing condition of the special common battery subscriber with subscriber mutual trunk. CONSTITUTION:In performing the identification of outgoing of the special common battery subscriber SUB of the private branch of exchange, the communication current in automatic outgoing is fed to the intra-office trunk IOT via the communication bus 1 of the network NW and the contact b is closed by operating the relay B in the trunk IOT. Further, it is detected that the outgoing of the subscriber SUB is an automatic outgoing. Next, when the subscriber SUB depresses the button S indicating the condition of outgoing and hooks off (automatic outgoing), and communication current flowed in the network NW is interrupted with the diode DO, the operation of the relay B is stopped to open the contact b, and it is detected that the outgoing of the subscriber SUB is a request call with the trunk scanning unit. |
