I *believe* the new Rider uses an HFP/HSP Bluetooth Profile to link to a helmet headset for phone calls and spoken directions. But I can't even confirm that in the manual.
I don't see anything indicating it has an audio-in/out port to hard-wire to an Autocom unit, OR even a built-in speaker... ? I suspect it has neither, and the Car Dock has a build in speaker for if you choose to use the GPS in your car as well.
*If* the above is correct, you'll need an Autocom Bluetooth
unit for the TomTom Rider to talk to the Autocom.
I have a Sena SMH10 on my helmet, and I'm sure that the Rider will talk to it using HFP/HSP to deliver spoken directions and its Cell Phone capabilities.