1.  Introduction

etrex cables are extremely expensive considering it's not much beyond an ordinary keyboard cable,  but costs twice as much as a keyboard cable with keyboard. So if you belong to the crowd that refuses to be ripped off, you can easily make your own etrex cable that is as reliable and robust as the original at a fraction of the price.

2.  Things you'll need

The first step is to get a plug. You will actually get two plugs for $10. You can even specify their color (mine is yellow, naturally).

While you wait for the plug to ship, get an RS232 plug and a cigarette lighter plug (if you plan to power the etrex that way).

Now all that remains is to assemble the plug - a 20 min job. The picture below and this document is all you need to complete the cable.

If you are wondering what to do with the second plug you've got and you use your etex with your bike, check out this idea