| 摘要 |
PURPOSE:To protect the possessor of a telephone set from a mischievous call or wrong dial by sending a call signal when a number corresponding to a DTMF signal sent from a caller after incoming operation is coincident with an identification number. CONSTITUTION:A signal sent from a caller as the identification number, that is, a DTMF signal is received by a DTMF signal reception circuit 32, which is connected to output a coded signal to a control circuit 25. A reception number memory circuit 33 storing a received number by the DTMF signal reception circuit 32 and a number collation circuit 34 or the like collating the number stored in the memory circuit 33 are provided. When the number corresponding to the DTMF signal sent from the caller after the incoming operation and the identification number are coincident, a call signal is outputted and the operation of a timer circuit 5 switches the operation/nonoperation of the caller selection operation is selected. Thus, the possessor of the telephone set is protected form a mischievous call or a wrong dial.
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