Ensure you are using the original data cable provided with the unit. Try a Different Port:
Ensure the communication settings in your software (e.g., Baud Rate, Parity, Stop Bits) match the hardware settings on the unit itself. Important Note on Legacy Systems geomaster gm2020 driver download link
Often, the driver is bundled with the Geomaster Data Management Software . Installing the full suite typically installs the necessary drivers automatically. How to Install the Geomaster GM2020 Ensure you are using the original data cable