I have an old Garmin GPS III that I want to use with my Treo 650 in the car, so I bought one of these cables from Semsons:

http://semsons.com/igapppdalica.html

The first cable did not work (see below), so Semsons sent me another. Same deal.

I've tried TomTom, cotoGPS, and GPSCompass. My Garmin is set to NMEA, baud rate 4800, and the apps on the Treo are configured likewise. (For TomTom, I select "other NMEA GPS".) All say "GPS off", or "no GPS detected", etc. Note that when I connect the Garmin to a Linux box and "cat /dev/ttyS1" I see constant NMEA data on the screen, so I know the GPS is OK.

This is my first purchase from Semsons, but I've heard good things about them. It seems unlikely that I got 2 bad cables. Any other ways to diagnose what might be wrong with the cable (or my Treo). Any thoughts would be appreciated.