| 摘要 |
PROBLEM TO BE SOLVED: To provide a telephone set which can solve the problem that when a telephone line used for the telephone set is connected after power is turned on, a side tone cannot be reduced, and easily optimizing the side tone by only performing a usual operation without requiring a special operation. SOLUTION: Upon capturing a line, a DTMF signal transmitting part 102 outputs a DTMF signal indicating the number of a telephone set of a calling destination via a 2-line/4-line conversion circuit 101. A DTMF signal level detecting part 103 detects the signal level of a side tone signal as a DTMF signal returned from the 2-line/4-line conversion circuit 101, out of the DTMF signals output from the DTMF signal transmitting part 102. A side tone adjusting control part 104 adjusts the impedance of the 2-line/4-line conversion circuit 101 on the basis of the signal level detected by the DTMF signal level detecting part 103. COPYRIGHT: (C)2011,JPO&INPIT
|
