How to Connect a GPS Receiver to a Psion Using the PsiWin Cable

1. Bare GPS Data Lead

The cheaper GPS data leads usually have three or four wires. Often one of these is a DC power supply. There is always a ground and a 'data out' line. Many models also support upload to the GPS and these will have both 'data in' and 'data out' wires.

WARNING : It is crucial that you do not connect the DC power cable to the wrong terminal - doing so could prove fatal to your Psion and/or GPS.

Pay careful attention to the GPS manufacturer's colour-coding used for the data cable. This information is usually included in the user manual.

[Incidentally, if you're here by mistake and looking for the connections for a female plug to connect your GPS data lead to a PC just swap the connections on 2 & 3 !]

2. GPS Data Lead With Serial Plug

If your GPS data cable has a serial plug already then it is probably a 9pin D female plug wired for direct connection to a PCs serial port. A null-modem adapter is required to connect this to the PsiWin cable and thus to your Psion.

Strictly speaking, a GPS only requires connections 2-3, 3-2, and 5-5 to be made. However, I hate doing only half a job and if you fully populate the adapter then it will also connect your Psion to a modem or printer. You can also use it with two PsiWin cables to connect two Psions together although this is only really useful if at least one is a Series 3c/3mx

Looking about the web it's pretty easy to find the connections but I was less than impressed with the representations because most fail to illustrate the simplicity of the layout on a 9pin plug. Having wired a few I sketched this which I hope will be useful:- if you set the two plugs down with their solder terminals facing each other, then this is how it would look.

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Last updated 16 February 2000

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