Legacy Garmin GPS Units

Many of the older Garmin GPS units are no longer supported by BaseCamp. In addition most desktop PCs (Windows and mac) do not have serial ports so you have to use a USB-Serial adapter to connect devices that use the old round or flat 4-pin connectors.

Visit this Garmin webpage for an explanation of the problem.


Solution is GPSBabel

The solution we have found is to use GPSBabel.

This was the engine used by OMNC to communicate with these devices and is available for Windows and macOS devices.


Download and install the appropriate version for your device from the GPSBabel website.

The installation includes a very good user interface that enables you to accomplish transfers in both directions.


USB-Serial Adapter

The one I currently use is the Plugable USB to RS-232 DB-9 Serial Adapter (Prolific PL2302HX Rev D Chipset).

This is available from Amazon UK, just use this link.

There are other devices available, just make sure you get the correct drivers for your adapter and OS.


Sending Route(s) to GPS

Export Route as GPX File

Using GM (Windows) or RTW (macOS) select the file containing the route(s) you want to sent to the GPS and export it as a GPX file.


Using GPSBabel to Send File

Start GPSBabel and select Input as File and format as GPX XML.


Then click on File Name(s) and use selection screen to find your file.



Now select the Output. It is device and Format is Garmin serial/USB protocol.

Then click on drop-down list for Device Name and you will be shown available serial ports.


In this case the choice is the device in COM4


Click OK and the transfer will start.


And when it completes a message is displayed.


Receiving Data from GPS


When you receive data from the GPS you actually get a dump of the entire GPS contents sent into one file.

Just revers the setting for input and output and select the file to receive the data.


You get the transfer screen and the usual message when complete.