Connecting the GPS receiver
While we like to think of Cetus GPS as a great tool, it is really not worth much without a GPS receiver connected to the Palm.
GPS clip-on receiver
If you have not yet bought a GPS receiver, you might want to consider one of the GPS clip-on receivers available. There are both pro's and con's for this solution. You do not need to handle two units with a cable in between, but on the other hand you do not get a working standalone GPS receiver.
Connecting a GPS receiver via a serial cable
If you have a GPS receiver with a standard PC serial cable, you may use a standard Palm modem cable to connect your Palm to the GPS receiver. You can even use the hotsync craddle if you have a standard null-modem adapter. You can buy the null-modem adapter at the local computer store or maybe solder one yourself. The null modem is simply two Canon 9 pole male connectors with pin 5 connected, pin 2 connected to pin 3 on the other connector and pin 3 connected to pin 2 on the other connector.
Garmin
Most Garmin GPS receivers use the standard round Garmin connector or the Garmin eTrex series connector. Cables for both are quite expensive at Garmin, but Blue Hill's Innovations and Pfranc sell some high quality connectors and Palm-Garmin cables World wide. If you buy a cable from them, please let them know, that they were recommended by Cetus GPS.