[Barry Carter] had a Pretec compact flash GPS adapter for his PDA and really liked how it worked. The problem was it took up the CF slot so he wasn’t able to add any flash memory to the device to store larger maps. He opened up the device and discovered that it only had five wires attached to the compact flash portion. The lines came from an NMEA chip and he used a scope to figure out the port settings. All that was needed was an RS232 converter. With the new packaging he was able to plug the GPS portion into the PDA’s serial port and use a larger CF card for storage.