| 摘要 |
PURPOSE: A circuit for detecting a ring signal and a CID(Caller ID) in a complex type wired communication terminal is provided to detect a ring, and to output a control signal by a CPU in a hook-off state, then to form a speech path through a switch, thereby stably detecting the ring and the CID. CONSTITUTION: A ring detect block(130) detects a ring signal, and supplies a signal in accordance with the detected ring signal to a CPU(110). A CID check block(122) detects a CID in a telephone function circuit(120). The second switch(SW2)(144) forms a path between a connection terminal(148) and the CID check block(122) by a switching control signal. The CPU(110) outputs the switching control signal to the second switch(144) if the detected ring signal is inputted, so that the CID check block(122) can detect the CID.
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