The cables we sell, provide a USB Serial connection to and from the GPS unit. It is not possible to access the waypoints, tracks or routes on the GPS directly. You need some software in order to communicate with the GPS unit. Typical software include Anquet, Memory Map or Fugawi. Please note that you will have to purchase them from another supplier. It is possible to download free software such as Gartrip, GPS Babel or GPS Trackmaker.
In order to set up a working connection between your GPS and your computer, you firstly need to install the drivers. These are supplied on a mini CD along with the cable. If you have lost the mini CD, or cannot access it from your computer, and are using a eTrex Cable, this uses PL2303 USB-Serial converters, which can be downloaded from here. For the GPS 12, 38 and 40 cables, they require the CP210x drivers, which are available here. Once you have followed the instructions on the screen.
Once the drivers are installed, please insert the cable into a free USB slot. Once you computer has identified the drivers for the cable, you now need to identify the comm. port number which has been allocated to it. To do this in Windows 8 or 10, you need to search in the Windows menu for "Device Manager"
Click on the icon "Device Manager"
Now expand "Ports"
In the list, there should be "Prolific USB to Serial Comm Port (COMX)" or for the GPS 12, 38 and 40 Cable it should be Silicon Labs CP210x USB to UART (COMX)". Take a note of the ComX number as you will need this for the next stage.
Next open GPS Trackmaker
Now go to the "GPS Menu" and choose "Garmin Interface"
In the "Available Comm Ports" section, Choose the same number as you found for the cable comm. port in device manager.
Next click on "Product ID"
If you are successful in setting up a connection, you should see a message such as "eTrex Legend Version 3.9". You can now send and receive waypoints, tracks and routes to and from your GPS.