Many newer Garmin GPSs are not able to connect to a PC because they now use proprietary protocols. In order to transfer routes marks and track logs, use the GPX Import/Export feature and copy the files to/from the device using Garmin's own software tools. The section below applies to some older Garmin devices.
The Memory-Map software is able to communicate directly with some older GPS units made by Garmin, connected by USB or Serial port.
Communication with a Garmin is bi-directional, and you can use the software to program waypoints and routes into the GPS, and retrieve a track log from the GPS, as well as plot your current position.
To set up the interface, first put the GPS in Garmin mode (Setup menu, Interface, GRMN/GRMN).
Next click on the GPS / Setup menu command, and select Garmin in the manufacturer field.
The only other setting you need to make is to select the COM port number you are using. On a desktop with integrated serial ports, the correct setting is "COM1:" or "COM2:". If you are using a USB-to-serial port coverter, click here.
Now you can see the commands to transfer data are enabled in the GPS menu.
When you are transferring long complex routes or tracks to the GPS, you may exceed the capacities of the GPS. The GPS Limits section of the dialog allows you to tell the software about the limits of your GPS. If your GPS manual does not specify these limits, it might take some experimentation to get them right.
Waypoint name length. By default, mark/waypoint names are truncated to 6 letters and made unique. If your GPS supports more than 6 letters in the waypoint name, increasing this value can give you a more recognizable name on the GPS.
Waypoints per Route. When you send a route to the GPS, if the number of waypoints exceeds this limit, it is sent as a number of separate routes, each containing the maximum number of waypoints.
Points per Track. When you send a track to the GPS, it may get truncated if there are too many trackpoints. This setting allows the software to reduce the number of points to something the GPS can handle.
If your Garmin GPS supports direct connection to a USB port (newer models are supplied with a USB cable), select USB in the Model field. You must install the Garmin Mapsource software, which includes the USB driver for the GPS. If this is not supplied on CD with the GPS, you can download it from Garmin's web site.
Note that some third party USB-to-Garmin cables include an integrated USB-to-serial convertor and have virtual comport drivers. In this case you must use the Serial setting in Memory-Map. The USB setting is only for specific models that have a USB interface built-in to the GPS.
If you want to use the British National Grid coordinate system on your Garmin GPS, make sure you have the following settings selected on the GPS unit:
Interface: Garmin
Datum: GB Ord Srvy
Position format: British Grid
If you select the British Grid with the WGS84 datum, the GPS display will show incorrect grid coordinates.
To display British National Grid coordinates in Memory-Map Navigator, select the Mode / Position Format / British National Grid. This setting does not affect communication with the GPS.