| 摘要 |
PURPOSE:To connect smoothly an incoming call on a central office line and transfer the call to another extension by connecting a device, which can detect an additional dial for central office line incoming at night, to a trunk. CONSTITUTION:A night changeover switch of an attendant board 14 is depressed, and a central control equipment 2 which receives this information switches and sets information of the extension calling system due to additional dial to a memory device 3. If a call comes from the other party office at night, the call is detected by an incoming trunk 1, and it is reported to the equipment 2 that the call comes, and the equipment 2 reads the incoming system of the trunk 1 from the device 3. Thereafter, the trunk 1 and a PBR signal receiving circuit 6 are connected through a path (i) of a switch network 5 to make it possible to receive the additional dial from the other-party office, and a dial tone DT indicating the receivable state of the additional dial is sent to an originating subscriber of the other-party office. The additional dial is analyzed, and the trunk 1 and an extension 7 are connected through a path ii of the network 5 to make the service possible. |
