After more research, I came across some information that the old NBT Head Unit wouldn't be able to support voice services from the 4G module. Has something to do with VOIP.
I don't really want to update the HU, so I'm contemplating some other options, including some type of Connected Car telematics, but haven't gotten too far. There are several companies out there that want to track EV battery health, but they seem to depend upon the built-in connectivity
