Power Control Switch. Set to “ACC” when using a 12V AC-DC power adapter to supply power to HD-8.
Wiring Harness Socket. Connect the red ACC and yellow VCC wires (solder or twist them together) from the supplied cable to the +12V input and the black GND wire to the ground input of a 12V DC power supply.
Combined Frequency Input. When the vehicle factory audio outputs High, Mid and Low frequencies for the Left and Right channel, you need to use the combined frequency input. “FL+RL+IN5” are used for the Left channel and “FR+RR+IN6” are used for the Right channel, to combine the frequencies for Left and Right channel signal input. This is not relevant for home use.
Center Left and Right channel Amplified Audio Outputs. This is not relevant for home use.