Communication controller and the communication state control method

Reproducing apparatus 100 includes a HDMI transmitter 150, a device authentication processing unit 172 of the CPU 170 connected to the HDMI transmitter 150, the connector 110 connected through the gate switching means 120 to the connection point of the HDMI transmitter 150 and CPU 170 DDC and it includes input and output unit 111, a. The device authentication processing unit 172 is configured to implement the DDC communication with the connected output device DDC input-output unit 111, to implement the internal communication between the HDMI transmitter 150. Current adjusting means 130 and the communication target switching means 171 of the reproducing apparatus 100, a potential corresponding to the signal waveform of the SDA when DDC communication at the connection point of the gate switching means 120 and CPU 170, a control to be lower than when an internal communications to.