Well, if the cable is good, you only have the jack, the patch cords, or something stupid. Look at the line cords that make up the patch. Since it's the outer pair, is the cord maybe nicked? How about the "crimps"? Do the black and yellow wires seat all the way to the end of the plug? I had an 8-pin fall out in my hands once...it only took about 3 weeks to find it.
Last, but not least, you could make up a jack with all the pins shorted on one end and meter out the conductors, looking for opens. I'd like to tell you that you can read the voltages on the pairs, but you can't. The voice pair has 38 volts DC, but the data pair doesn't settle. You can read the same 38 volts on one of the data pins to one of the voice pins, but that's not much.
Carl
