: You can now modify frequencies (VHF or UHF depending on your model), PL/DPL tones, and assign functions to programmable buttons P1 through P4.
You typically need a cable with a USB Type-A connector for your PC and an 8-pin (RJ45-style) connector for the radio's microphone port. Many modern cables have built-in RIB (Radio Interface Box) logic, eliminating the need for a separate hardware box. motorola gm339 programming software