Best idea is to get a xd to usb card reader and just take the card out of the camera... much faster d/l of pics. But if you still wanna giver-a-go the cable is a trs (tip-ring-sleeve) 2.5mm to female db9 serial cable. So there's three conductors. Transmit, recieve and ground. If you wanna wire one up by splicing some cables ya got see here.http://pinouts.ru/DigitalCameras/olympus_d400z_pinout.shtml
Or buy one from:http://ad7gd.net/vx6/datacable.htmlhttp://www.pccables.com/87008.html
Basically the wiring you need is 2,5,3 mapped to Tip-Ring-Sleeve.
There are other variations of this cable. It was used for many old school calculators and cameras among other specialty io.
Most are of the 2T-5R-3S design. I doubt anything will fry if you x-ed them... just wont work.