Are you looking to expand the of your GM300, or just change basic frequencies? Share public link
Downloading the free software is only half the battle. The GM300 is a DOS-era radio, meaning the programming interface is unique. You cannot use a standard USB cable. motorola radius gm300 radio doctor free
A DOS-based system does not understand USB; it requires a direct hardware interrupt (IRQ) to function correctly. However, since Radio Doctor runs under Windows XP, it can use a USB-to-serial adapter, though a native serial port is more stable. The data flow is: Are you looking to expand the of your