automatic audio switch

I'm installer of police car equipment.My client want to automatic switch from the car radio to the two-way radio, so they use the same car speakers?The car is a 2013 Dodge Charger.Radio is a Motorola cmd1250.I found a Russsund Automatic Source SelectorAB-3.2.  My question is will this work, or is there a better options? Please let me know.Thomas

Speaking strictly from a car audio point of view we accomplish that same goal by using mute wires and/or relays to break open the speaker wires. Is there a wire that goes to ground on the cmd1250 when it activates? If not you might be better off sticking 2 small speakers under the dash or on the sides of the console for this purpose.To master and control electricity is perfection. *evil laugh*

racerjames76 wrote: Speaking strictly from a car audio point of view we accomplish that same goal by using mute wires and/or relays to break open the speaker wires. Is there a wire that goes to ground on the cmd1250 when it activates? If not you might be better off sticking 2 small speakers under the dash or on the sides of the console for this purpose.

If the CMD1250 doesnt have a wire that goes to ground when it activates why couldn't you use a Pac TR-7 trigger output module that send a (+) trigger out to the relays with a audio signal and use the relays to break open the speaker wires? Just a idea.I drink current, eat ohms, and bleed voltage

Could you tell me hoe to build a relay switch. I have a ruff idea on how to do it. A list of parts would need to build the relay.

Sorry it took so long for me to get back to you. I've been busy at work and haven't had much time to do anything. I made a schematic of how the audio switcher would work. I only made the diagram for one speaker but you need two relays for each speaker that's being added. So all you need is some 18AWG wire, SPDT 30/40A relays (number depends on the amount of speakers in the system), and a PAC TR-7. I drink current, eat ohms, and bleed voltage