Disconnect cable, key up on a known safe frequency (e.g., 446.000 MHz for ham use, or your licensed business channel).
Most local two-way radio shops sell or include CPS with a programming service. Typically, they charge $50–$150 for the software license. Examples:
Open Device Manager → Ports (COM & LPT). Note the COM number assigned to your cable (e.g., COM4). In CPS, go to File → Preferences and set the same COM port. Disconnect cable, key up on a known safe frequency (e
The Motorola GM338 is a professional mobile radio (PMR) used in commercial, public safety, and amateur radio applications. To program channels, tones, power levels, and other settings, Motorola CPS (Customer Programming Software) is required.
If you are a business, dealer, or certified radio technician, request access to Motorola Solutions Online. After approval, you can download the exact CPS for GM338 under “Legacy Products.” Examples: Open Device Manager → Ports (COM & LPT)
Click Read from the radio. You’ll be prompted to turn the radio off/on. Follow the instructions. If it fails, check your cable drivers and COM port speed (should be 9600 or 19200 baud).
| Error Message | Likely Cause | Fix | |--------------|--------------|-----| | “Communication with radio failed” | Wrong COM port or cable driver | Reinstall Prolific/FTDI driver; try COM1–COM4 | | “Codeplug too new for this application” | CPS version older than radio’s firmware | Update CPS to a newer build | | “Checksum error” | Corrupted read/write | Retry; if persistent, codeplug may be corrupt – requires factory alignment | | “Radio not responding” | Cable not fully seated or radio OFF | Reseat D-sub connector; turn radio ON | The Motorola GM338 is a professional mobile radio
No. CHIRP does not fully support the GM338. Some people have tried modifying CHIRP for Waris series (GM338 is part of the Professional Series, not Waris). Do not attempt – you risk bricking.
The only safe software is Motorola CPS.