| 摘要 |
PURPOSE:To reduce a time to ask for calling back and to improve the certainty of call back by memorizing the telephone number of a demanded extension subscriber and a telephone number of trunk line subscriber, making a call to the extension subscriber and the trunk line subscriber after the circuit is recovered and automatically connecting the extension subscriber and the trunk line subscriber. CONSTITUTION:When there is an incoming call, an incoming trunk ICT detects this call, and informs a central control device CC of this incoming call. The central control device CC connects the incoming trunk ICT and input a register trunk IRT and informs a trunk line subscriber X that the selection signal is acceptable. When the trunk line subscriber X desires the calling back, he dials call back registration number, extension subscriber's number for which call back is requested, and the telephone number of the trunk line subscriber X. These numbers are received by an input register trunk IRT and stored at a memory device MEM by actuating the central control device CC when the data reception is finished. When the recording to the memory device MEM is completed, the completion of call back setting is informed to the trunk line subscriber X by sending service setting completion tone. |
