| 摘要 |
PROBLEM TO BE SOLVED: To supply input signals to an external connection equipment even when power is turned off and to perform bidirectional communication. SOLUTION: A level detector 7 detects the input level of a tuner 11 and an external device connection terminal 15 and a gain control circuit 8 controls the attenuation amount of a variable attenuator 5 and performs adjustment so as to be a desired level corresponding to a detected result. A switch 3 and the switch 14 are linked with the ON/OFF of the power and a contact point is switched so as to connect a system connection terminal 2 and the external device connection terminal 15 when the power is turned off. Incoming signals outputted from an incoming signal generation circuit are passed through a branching filter 4 for separating the incoming signals and outgoing signals and outputted from the system connection terminal 2. |
