To preface this question: I'm not able to get to a parts store any time soon. I'm well aware that I could buy what I need, but I'm trying to make do with the tools and hardware I already have.
I found a cable that is 10pin RJ-45(48?)-to-USB. The jack has leads on 1(red), 4(brown), 7(black), 9(white), and 10(green). Not sure what's Tx, Rx, ground, data, uni/bi-di, etc. Nothing is striped. Upon cutting the jack from the end of the cable and peeling back the insulation, there was no lead for 4(brown) that I could see. Could the metal insulation have been grounded to 4(brown)? Is there a way to salvage this cable with an 8pin RJ-45 to be used as a console cable for my Linux box router?
EDIT: The cable appears to be part of a UPS from one of the several home security systems in the building.