| 摘要 |
PURPOSE:To decrease the number of cables between a telephone exchange device and an attendant board, by connecting various types of information for communication on a loop type line with digital multiplexing between an automatic exchange device and the attendant board. CONSTITUTION:An incoming call to an incoming trunk 2 is informed to a central device 10, and the device 10 transfers a code showing an incoming display to a main loop interface device 8. The device 8 inserts an incoming display code to a slot for control signal and transmits it to a transmission line. A follower loop interface device 7 detects the incoming display code and transfers it to a signal converter 6. The converter 6 decodes the incoming display code and performs the incoming display to an attendant board 4. When an operator of the board 4 gives an answer to the incoming call, the device 10 closes a channel between a trunk 2 and a position trunk 3. A voice signal is supplied to a talking circuit of the board 4 through the trunk 3. The voice of the board 4 is supplied to the channel of the trunk 3 for talking. In such a constitution, just two pairs of cables suffice for transmission and reception of data. |
