| 摘要 |
PURPOSE:To enable an operator at a trunk line switch box to make a connection when requested to peform origination, and to automatically call back the extension after a telephone call. CONSTITUTION:An operator at a trunk line switch box ATT, when getting away from operation after beng requested to perform origination to a trunk line CO and making a connection, presses a specific key to send information to a CPU through a control circuit ATTC and an information receiving and distributing device CONT, and call-back information is stored, corresponding to an extension telephone set STA, in an RAM. In response to an on-hook signal from the STA, the CPU scans and detects the on-hook state of the STA by processing information written in an ROM to check the call-back data stored in the RAM. Then, the CPU sends a call signal to the STA and also performs lamp display for a call-back connection on the ATT. The operator at the ATT is connected to the STA through an IOT by answering with a corresponding key. Thus, the B board operator makes the call-back connection without performing new operation, which is convenient when the call-back of a hotel switchboard, etc., is frequent. |
