I bought a Treo 90 at a garage sale for $6 and it came with a Holux GM-210 GPS receiver. Unfortunately, it came with no software.

I downloaded every free GPS program from freewarepalm.com, but only Navegador software would recognize my GPS receiver. In case someone else has a similar situation, I did have to make a couple of tweaks to make things work (even with Navegador): Under GPS options, you must choose Serial (not autodetect), change the baud rate to 4800 and select NMEA as the protocol. After doing these things, you will need to do a warm reset. After the warm reset, go back and make sure that these settings are still good. Then you go to the information screen and click on the icon in the upper right corner. It should turn into two arrows and after a few seconds, you should see glorious GPS data. It was really cool. If you just need to test an older Treo with a GPS receiver, try Navegador:


FYI: Just some insight into why the other programs failed. I tried Cetus GPS, but it had a problem finding the serial port. Apparently, the older Treos have something strange going on with the serial ports (like the software doesn't know which serial port to specify). I believe this is where Navegador succeeded by dealing with the serial port in a more robust manner than the others. I also tried GPS Buddy and a couple others and none of them could recognize the GPS receiver.