Cliff, call Riverpark, (800) 442-7717 -they distribute the Xite system and are very helpful. You need a SD card not "SIM" card with the Xite system. They will need your Xite radio serial number and model number probably. Those are on a sticker on the Xite core unit, but you'd have to remove it to get to it.
My Winnebago came with a sheet of paper that listed all model numbers and serial numbers of the 3rd party devices installed. If you have that document you could find that info there.
If you don't have that info a call to WBGO support with your VIN and serial number should give them the ability to provide that info for you.
2017 Winnebago Adventurer 37F
2016 Lincoln MKX Toad