| 摘要 |
PURPOSE:To attain confirmation of operation without using a trunk line relay board by acquiring an outgoing trunk with a specific number for trunk designation acquisition from an extension subscriber and dialing of a trunk designation number. CONSTITUTION:When the extension subscriber dials a specific number for trunk designation acquisition by an extension telephone set STA, a central controller 4b detects the information and discriminates it as trunk designation acquisition by using specific number information stored in a storage device 5b. Moreover, when the extension subscriber dials a trunk designation number, the central controller 4b discriminates allocated position information of an outgoing trunk 3 corresponding to the trunk designation number stored in the storage device 5b to close a channel swithc 2 between the outgoing trunk 3 and the extension subscriber telephone set STA. |
