It's more than a cable
As far as I remember, it's not just a cable, it needs to be a pic unit or a PCMCIA card or a ktx card for your serial port, pcmcia slot or a card for a pci or isa slot in a desktop. These items are readily available from AB but they will cost more than buying a new processor. Last time I checked a ktx and PCMK card were like 1,700 US dollars.
My number may be off but it's not like you can just get a cable from radio shack.
Good luck,
try E-Bay
Marc