I managed to get my hands on a Garmin eTrex as the owner had upgraded to a newer fancier model. The eTrex seemed ideal for me as all I really wanted to do was take way-points so I could put the tracks on my maps…

After taking it on a few trips, I soon found that things wouldn’t be so simple: there wasn’t really a way to connect the GPS to a computer. Some found that it had a serial interface but that the cable (to many people’s irritation) is not supplied.

I soon tracked down a cable on Ebay that included a serial to USB converter, which is very handy as computers generally don’t have a serial port anymore. I bought my cable from the KaWaMall eBay Store in the United States (sold as USB & PC data Cable for Garmin Etrex H GPS).

Once it had arrived, I decided not to use the drivers that I assume where contained on the mini CD. Instead I went straight to the Prolific website (the manufacturer of the RS232 to USB converter).
I logged in using the guest account (username=guest, password=guest) and then clicked the link for the PL2303 USB to Serial Drivers.

I was working on a mac at the time so I grabbed md_PL2303_MacOSX-10.6up_v1.5.1.zip file. Once downloaded, I installed the drivers which required a system restart.

There where then some optional steps in the manual I followed. First you start up the System Information application. You can then locate the USB-Serial Controller in the USB category. Plug your cable in first, or choose File > Refresh Information once you have it plugged in.
Clicking on the controller should reveal that the vendor is Prolific.

You can then “check if the USB serial port device is setup properly” by running the following comands in terminal:

cd /dev
ls tty.usbserial*

The command should print “tty.usbserial”.

I then download LoadMyTracks which can be used to get the data off the Garmin. I selected “Garmin Serial” from the top drop-down box and then “usbserial” from the second. I selected KML as the output format and pressed “Acquire…”. Voila, it seemed to be working!

It took a while to finish, but I soon had my KML file which I opened in Google Earth where I happily saw a tangle of tracks and way-points.

That was step one done, but the information was a bit messy as multiple trips where joined together. See part 2 for how to clean things up.