linking my base radios via ROIP
Big Lebowski:
That's a great idea, and it will work easily with the Radio-Tone ROIP-2 interface box, but unfortunately if you plan to continue using your base radio "as a base radio," where someone else could sit in front of the radio when you are not there and use it to talk or listen on, you can't use Zello/ROIP on it. You would have to have two base radios and two antennas, and the antennas would have to be spaced far enough apart that one doesn't de-sense the other.
Now on the other hand if nobody will be trying to use the base radio when you are not there, then yes, you can use Zello/ROIP with just the one radio, and you can operate it from your cell phone. It really all depends on what functionality you want that base radio to have when you are not in front of it.
From my experience, we used the ROIP-2 on a Motorola CDM mobile in a small police department, and found out the hard way that once the ROIP-2 box was connected, that radio could no longer be used as a traditional base station. So we set up a second CDM in a closet on the other side of the building, put up a second antenna, and left it alone. Now the original base radio could continue to work as a base station, and the second one acts as the interface.