http://rallypilot.sourceforge.net/ is the software, here's his wiring directions:
Only three wires to hook up; from Palm TXD, RTS, and GND.
PalmPilot card edge (looking at the back, right to left)
1 - DTR (+3V to +6V non-standard)
2 - +3.3V
3 - RXD
4 - RTS
5 - TXD
6 - CTS
7 - GPI1
8 - GPI0
9 - NC
10 - GND
So you see that you need to connect pin 4 from the PalmPilot connector (card edge at bottom) to where RTS is on the CM17A (pin 7 DB9), and you need to connect pin 5 TXD from the PP to where DTR is on the CM17A (pin 4 DB9). Then also connect ground PP pin 10 to CM17A (pin 5 DB9). Notice that I connect TXD to the CM17A rather than DTR because I can control TXD but not DTR.
DB9 DTE pinouts (computer)
1 - DCD
2 - RXD
3 - TXD
4 - DTR
5 - GND
6 - DSR
7 - RTS
8 - CTS
9 - RI
Now if you are going to just hook up the CM17A to a cradle connector, remember that the cradle is wired as a DCE so it is like this:
DB9 DCE pinouts (cradle)
1 - DCD
2 - TXD
3 - RXD
4 - DSR
5 - GND
6 - DTR
7 - CTS
8 - RTS
9 - RI
Though because we wire the Palm's TXD to where DTR would normally go you cannot use the Firecracker as a pass-through to other devices.
I took the DB9 connectors off, and mounted the small board inside of my IIIx where the SIMM would normally sit; though I wrapped scotch tape around it. Since the Firecracker has a smart chip (PIC) inside it which validates the signature bits on the 40 bit stream prior to sending it over the air, I am able to keep it hooked to the serial lines permanently without fear of it broadcasting jibberish during hotsync etc -- since a valid 40 bit sequence would be unlikely especially considering how rarely RTS changes state during normal serial operations.
