Motherboard IRDA Header Construction:

This one is very fiddly to build unless you have the capability to produce a PCB and surface mount it. My preferred method is to gently bend the forward facing legs back crossing over any that want to join such as grounds. Then bend the resistor legs so as to allow the resistor to sit neatly just behind the package as in the picture.

Attach some light weight 4 core flex and then find some way to make it permanent. If you are putting it in a box then its probably not a problem for you. I tend to coat mine in glue to seal them up as they need insulation and mechanical support.

The opposite end of the cable just needs the connector attached.

All that remains is to check the pin layout for the IRDA port on your motherboard, check the manual!

You will need to enter your computers BIOS and locate the option to enable the IRDA port, note this usually takes the place of your second COM port. Select the option that says something along the lines of Full Duplex AskIR.

Once you boot windows it should recognise the hardware being added and deal with it itself. A new option appears in the control panel called 'Wireless Communication' or something to that effect.

That about wraps it up. If you bring another IRDA device within range or try to connect to it with your PDA/Laptop the PC should recognise what's going on!