Finding the legitimate software is tricky because Motorola no longer sells or supports RSS for the GM339. The software is considered "End of Life" (EOL) and is typically found via preservation sites or hobbyist forums.
Software is useless without the correct hardware interface. The GM339 uses a non-standard serial protocol.
“The GM339 is a 99-channel, 25W radio often used in European fleets. The software is hard to find because Motorola locked it down — but if you get the right CPS, programming is straightforward via a standard Rib-less USB cable (aftermarket) with a MAX232 chip. The trick: Windows XP 32-bit or a true DOS VM. On Windows 10, the programming times out unless you slow down the USB polling.”
Another gem from forums:
“I bought a ‘GM339 programming software CD’ on eBay — it was just a cracked R06.12.05 with a keygen. Malware alert! Instead, find the genuine Motorola RIBless cable (eBay/AliExpress) and ask for the CPS on radioreference.com or repeater-builder.com. People will share the original installer.”
The software, typically running on a Windows environment, utilizes a spreadsheet-style interface. Key areas of the configuration include:
Programming the Motorola GM339 mobile radio requires specific "Customer Programming Software" (CPS) and a compatible hardware interface. This radio is a versatile communication tool often used in growing organizations because of its extensive list of programmable features, such as 255 channels and advanced signaling. 1. Essential Software & Hardware motorola gm339 programming software
To program the GM339, you will need the following components: Software: Professional GP300/GM300 Series CPS.
Version Compatibility: Ensure your software version is equal to or newer than the one last used to program the radio (e.g., version 7.01 or later is common).
OS Requirements: While originally designed for older Windows versions (XP or 7), newer cables often support Windows 10/11.
Programming Cable: A specialized cable, often with an RJ45 connector for the radio side and a USB or Serial (DB9) connector for the PC.
USB vs. Serial: Standard USB cables with FTDI chipsets are highly recommended for modern PCs to avoid driver issues.
RIB (Radio Interface Box): Some older setups require a RIB between the PC and the radio, but "RIB-less" USB cables are now more common and easier to use. 2. Basic Programming Steps Finding the legitimate software is tricky because Motorola
Once you have the software and cable, follow these general steps:
Connect: Plug the programming cable into the radio's microphone port (RJ45) and your PC's USB/Serial port.
Read Radio: Launch the CPS and select "Read Device" to pull the current configuration (codeplug) from the radio. Configure Settings:
Frequencies: Input the desired Transmit (TX) and Receive (RX) frequencies.
Signaling: Set up PL/DPL tones (CTCSS/DCS) to filter out unwanted interference.
Custom Buttons: The GM339 has 4 customized buttons that can be programmed for one-touch access to specific operations. “The GM339 is a 99-channel, 25W radio often
Write to Radio: Once changes are made, select "Write Device" to upload the new configuration. 3. Key Features to Program
Caller ID: Enables users to identify incoming callers on the 14-character alphanumeric display.
Voice Storage: If the optional board is installed, you can program messages or memos up to 120 seconds.
Emergency Mode: Configure specialized signaling for "Lone Worker" or emergency status.
Because you are reading this article, you likely own a GM339 from eBay or a surplus sale. Be aware:
Before you download anything, you must understand that Motorola used two distinct types of software over the last 30 years.
Pro Tip: The GM339’s accessory connector pinout is critical. Pin 1 (Ground), Pin 2 (BUS+ / Programming Voltage), Pin 3 (Data), Pin 4 (Data). If you hear your speaker "thump" when inserting the cable, you have power; if not, your RIB isn't powered (RIB requires 9V battery or external 12V).