Connect a Palm Street Finder GPS to a Laptop

You can pick up the Rand McNally Streetfinder GPS for the Palm V for about $40 on Ebay. Problem is, if you don't have a Palm V, they aren't much good to you. I picked mine up at a garage sale for $10. After a little hacking I was able to get it to talk serial to my laptop. There is also a Streetfinder GPS for the Palm III. My guess is that this would work for it also, but since a don't have one I can't test out that theory.

To get the GPS to talk to a laptop you need to make a serial cable. You will need to connect to 4 of the pins on the GPS unit. Here is the pinout

GPS Pin	Serial Cable pin
1	7 RTS
3 RxD	2 RxD
5 TxD	3 TxD
10 Gnd	5 Gnd

Then just use any software that reads standard NMEA input. The CD that came with my streetfinder also had a laptop version and worked fine. A good simple gps program is gps diag.

Update Mar 15, 2004:

From Yuval Ofir
Hi. I used your idea to make a GPS reciever for my Notebook from my Magellan Companion for m500 series. The Comm Port is diffrent but here is what I had to connect :)

GPS Pin	RS232 Pin
7 - Gnd	5
10 - Palm RxD	2
11 - Palm TxD	3
15 - Palm DTR	7

It is working great on 2 other comp's, but i dont have RS232 Port in my Notebook, I just have to buy USB>RS232 Adapter :)

Update: Thanks to Eagan . He got a Palm III Streetfinder working with his laptop with one small change.

I thought that you would like to know that on the Palm III Streetfinder RTS is pin 4 and not pin 1. It took me a while to figure this out, but eventually I found the pinout for it:)

Update: I recieved an email stating

You should notice though that Magellan support told me the palmV Companion expects +/- 6V RS232 Levels. Certain computers output up to +/-12V. That can potentially damage the Companion. You should make sure your RS232 port doesn't go above 7-8 Volts.

Update: I got another email telling me about a pre-made cable. It is for connecting palm devices to a laptop. The url is (http://store.markspace.com/dc5sled.html). The only problem is that with that cable the gps would not automatically turn on. The emailer said he could put the gps in the Palm, turn it on that way and then connect to his laptop with this cable. My guess is that the cable is not connecting to pin 1 on the gps . That is the pin that tells the gps to turn on. Also the gps has to get a signal to this pin every few minutes or it will power off. Still you might could hack the cable to make it work better.