Does anyone know the programming protocols Motorola used on the old SM50 and GM300 radios? I ordered some of those USB to UART modules and have been having a ton of fun making them talk to each other with a C# windows form app and was hoping someone knew the digital ins and outs of the Motorola programming interface. I have several Motorola radios and, once upon a time, I had software to program them. Every time I tried since 2005 (even on an XP machine like I used before), these radios just dont want to talk to the Motorola software. I ended up giving my cables to someone else thinking they were no longer useful to me. I later found out that the software is not backwards compatible and using an older version software to program a radio that used a newer version software, the older software no longer works. I never did find the software I had used originally and everything online seemed to not work. But now with these serial communication chips, id like to take a shot at making my own programming software ~ I just dont know the protocol used to talk to these radios.

Does anyone have any insight other than tearing apart a radio and searching the datasheets?