opc-617

Hi all, Apologies if I'm posting in the wrong area here, this is my first post. Feel free to move it if need be. I have an older IC400PRO here in Australia that is just used for a personal CB. My car stereo has a mute input signal on it (unsure whether this is +12V or GND at this stage), and I...

Is there a way to wire in an external speaker to the Icom F1721 using the OPC-617 accessory cable so that both transmitted and received audio come through the speaker? I am looking at using this radio in a Mobile Incident Command vehicle and I would like to put an external speak in another part...