I have bought “GPS City Dell Axim X5 Male PS2 Cable for GM-210 (67032)” from
www.GPScity.com for $9.95+TAX&Shipping. To see it, do a search at
www.GPScity.com
The item includes a car charger; I have tested it and verified that it does output +5.3V @1A . Thus, it seems to be more powerful than Belkin one.
The cable splits into an Axim X5 40 pins plug and PS2 (mini DIN 6) connector, which can be directly connected to serial GPS receiver GM-210 (aka Holux). I guess it can also be directly connected to Rayming (TripNav) serial TN-204 because GM-210 and TN-204 **seem** to have identical pin-outs. I also guess that you can make (or, perhaps, buy) a very simple and cheap adaptor to connect it to most serial GPS receivers. For example, I use it with Garmin GPS 18 PC.