What version of Windows are you running? Is it 32 or 64 bit? The USB to RS232 converter cable available from Garmin only supports 32 bit operating system. Garmin does not support 64 bit operating systems for serial to USB conversion. If your computer is a 64 bit system, then the correct driver is probably not being installed. You will need to contact the manufacturer of the cable to obtain the correct drivers.
If it is 32 bit, have you followed the installation guide in our FAQ How do I install Garmin USB to Serial Converter driver in a Windows 32-bit Operating System?
If you continue to have problems with the drivers in a 32 bit environment, contact Product Support by phone for further assistance.
