ive got a real problem. customer needs 2 feeds from upstairs suite to downstairs phone room. i was able to run cable from suite to upstairs phone room. cat 6 plenum. from there i had to tie into old house 50 pair cable to downstairs phone room. i have jacks installed at both ends. when i tested the cable with tester in the suite it passed and the said there was voltage on the line. it goes back and forth from pass to reading voltage on line with both cables. when i test from the phone room it says pass and doesnt see any voltage. can anyone make sense of this. i dont see how any voltage can get on the line and when i put my tone sender on the pairs it doesnt light the light. thanks dave

I say that it is a stray issue that is of no significance. Keep in mind that 50 feet of CAT6 cable is the equivalent of about 100 feet of CAT3. Mixing categories isn't advised, but depending upon what you're doing, it shouldn't really matter. If you can't pick a voltage reading with a real volt meter, then don't worry about it.

By the way, just because a cable has more than four pairs, that doesn't make it old! We install brand-new 50 pair tie cables all the time.

thank you for the feedback. i dont thing it really has any voltage but when i go back i will check it with a meter.