In short, my old set-up used a outside speaker and a hand held mic to transmit.
I since changed to an intercom system. Both driver and co- driver can communicate even when one is outside the vehicle.
Radio communication is voice activated.
Our helmets have speakers and mics.
Fine when you are wearing your helmets. There is a lot of waiting and I like listening to music during that time but I don't want to have to wear a helmet during that time.No stereo system in the truck. No radio, no speakers.
The intercom has "Bluetooth" and I can listen to music through my Iphone but it is not loud enough. Bought a small speaker for the phone.
When it comes to radio stuff I know very little.