| 摘要 |
PROBLEM TO BE SOLVED: To provide a caller number transfer device which can transmit the telephone number of a caller to a receiver even through a transfer telephone set and a private exchange. SOLUTION: When the caller number transfer device 10 of a transfer telephone set 23 makes a response at the time of dial calling from the caller, the telephone number of the caller is converted into a modem signal and is sent to the caller number transfer device 10. The caller number transfer device 10 receives the modem signal, converts a PB signal and temporarily stores it. A number signal is sent from the transfer telephone set 23 to the private exchange 25 as a call signal. In a caller number transfer device 30 in the private exchange 25, the PB signal is converted into the modem signal and is stored. The telephone number to the caller is transmitted by a protocol similar to the communication line of a telephone company with respect to the receiver as a private telephone. The receiver recognizes the telephone number of the caller and can be on the telephone.
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