Here is a instructable to build a datacable to connect your Garmin with the PC via USB.
I made this for my sister.
The idea is from:
There you can also find other instructions to build a datcable- but just for serial connection.
The solution at the named page wasnt good enough for me. I want to have a better conection.
Step 1: Disassembly
look at the intructable from : zzpza
Garmin eTrex H Dissassembly
be carefull while demounting the black rubber around your garmin. it rips easily.
after that you have to remove the tabe.
with a sharp knife you can easily open the cover.
unplug the plug on the pcb in the gramin.
Step 2: Welding1
weld 3 flexible wires on the pins for the normal garmin plug.( at the inner side)
then drill a hole through the housing and put your wires through.
Step 3: Plug
add a plug which is easy to remove.
Step 4: Sub D 9 Pin
take an sub d 9pin plug and weld on pin 2, pin 3 and pin 5 cables and connect them to your plug for the plug you welded on the garmin..
Step 5: Usb Adapter
if you dont have a serial adapter buy on.
i bought a logilink from conrad electronic:
LOGILINK USB 2.0 SERIELL ADAPTERc
conrad # Best.-Nr.: 990457 - 62
logilink #[Teilenummer: AU0002B]
Step 6: Garmin Driver
download the garmin comunicator plug in for firefox.
it is called:
Garmin Communicator Plugin
you will find it on the garmin homepage.
it also works with firefox 4.
i also useed it with windows 7 and it works very well.