Russound caa66 and Proficient 'The Source' wall controller compatible?

 My customer provided these for installation, but I am unsure if they will work together? Can anyone confirm if they are compatible with each other?

Considering they're from entirely different companies, and competing ones at that, I'd say that's pretty unlikely.

 I had a feeling this was the case, and checked the pinouts in the manuals. They get their power and data on different conductors.

I wouldn't even start to make any assumptions based on the pin configurations.  Devices like these are basically serial keypads.  Each vendor is going to have their own format, most (all?) of which is undocumented.  So even if two different vendors happened to use the same pinouts, or even the same kind of signal, the protocol between the devices is not going to be the same, nor even 'close enough' to be workable.  This isn't a 'bad thing' as much as it's just the way devices like this are created.  There's no appreciable market for compatibility.