^^^That still doesn't explain what he's using it for or it's intended purpose. I thought I had seen most all combination of scanners/diagnostic cabling and equipment and this one has me scratching my head.

Splint, I would Ohm out the cabling or just hand him the pieces to assemble what he needs. If he is using that on a
scanner or the like, he will want to make sure of the polarity. They aren't always standard and will/might damage the scanner or serial port. I've experienced a home made cable disaster first hand(not my doing). If you do find out what he is using it with Splint, would you pass the info along? It's got me intrigued.