I have 2 X Motorola UHF GM350's which I program from my laptop, without a problem via a USB to Serial cable.
The RSS reads and writes, no problem.
I got a third one recently but for some reason it refuses to be programmed. I had to get it done locally by a dealer.
I have tried to upload new codeplugs into the radio but error messages appear, saying 'unable to connect to radio' and then 'this version of rss not compatible with the codeplug' etc.
The radios not faulty, because the dealer was able to do it (for 50 quid!).
I would have thought that my RSS - the only version I could lay my hands on

I'd appreciate any help, because I don't fancy forking out every time for a frequency change.