Just a thought. My XKR (2000) is equiped with the Motorola factory telephone option. The device is not working anymore and if it did, you can't use it because tech moved one with G4 and G5 and the Motorola is G2. To use the wiring present in the car, it might be an option to wire it so an USB connected smartphone can be installed in the console and work thrue and with the buttons on the steering wheel and head unit. Anyone tried this? Are there cables available?

 

The complicated answer is that you can wire in an old style Bluetooth adapter and get hands-free phone calls through the car speakers (and it mutes the radio) plus Bluetooth stereo music with a bit more work (basically working around the fact that the stock radio has no aux input). So, some of the car controls would work (radio volume), but most would not, as picking up a call and hanging up would be done through a keypad supplied by the Bluetooth kit. The kit can be wired in either by tapping the well documented wires under the arm rest or procuring a pre-made connector for a cleaner setup.

There is a chance pushing the various phone-related buttons in the car result in digital messages on a corresponding data bus (SCP, ISO-9141?). A small board computer with a suitable bus adapter could be made to capture these messages and then somehow use them in a Bluetooth context.

 

I was thinking more about just a wired solution instead of bluetooth. All the wires from the Motorola connection transfer to an USB hook up and plug it in the smartphone. Not to have music and other gizmose from the smartphone and just pick up the call with the buttons already on the steering wheel. With the sound system already there i have enough options with radio, cassette and disks.

 

The simplest solution is Bluetooth as already mentioned, either wired into the connections in the armrest or even simpler, one that plugs into the lighter socket. Neither of those options gives you music streaming, just phone calls.

There are many other solutions to this, but none that I know of will give you steering wheel control of the calls.