telephone crosstalk - eliminate with Cat5?

[PPettit]

One of our remote offices has a problem with their telephones. Each phone has the same two lines, and when you're on one you can hear what's being said on the other. It's faint but still clear enough to understand.

I connected some phones directly to the point where they enter the building. Since I could no longer hear the crosstalk, this leads me to believe that there is a problem with the wiring running throughout the building and not with the phone company's wiring to the building.

Both lines come to each phone jack via some ancient-looking beige four-conductor cable (Line1 is red/green and Line2 is black/yellow).

What I'd like to know before I waste a day or two is whether I can solve this problem by replacing the old cable with some Cat5 that I have on hand. Would I still experience crosstalk with the Cat5 if I run Line1 on the blue pair and Line2 on the orange pair? The better quality and frequency of twists should eliminate or significantly reduce the degree of crosstalk, correct?

 

[Dexman]

Sometimes high loop current can cause crosstalk. Also running the 2 telephone lines on seperate cables as opposed to using both pairs of a single 2 pair cable might help.

 

[skip555]

you dont need cat 5 but you do need something better than the quad wire you have now. whish has no twists

quad wire was /is famus for causing crosstalk.

you need to pull new cable.

with the cable price being bascially the same on cat 3 vs cat5 I would go ahead and run the cat 5

twisted pair of any cat rating will clear up your problem

 

[wires]

four-conductor cable (Line1 is red/green and Line2 is black/yellow)"

This is known a quad cable and it is quite succeptible to crosstalk since it does not use twisted pairs.

The easiest fix is to replace it with cat5 and put line1 on the blue pair and line2 on the orange pair.

 

[PPettit]

Thanks for the confirmation, guys.

 

[daronwilson]

Did you try each phone at the D-marc where they come into the building? WHile is it quite likely the quad, i have fought this in Cat3 situations with multiple two line phones only to find out one phone had a crosstalk issue in the set, more than once, generaly the lower end panasonic phones. Before you rewire, i would unhook all but one phone and test. Pick up line one, dial a recrding at the movie theater or something, put it on hold and pick up line two, dial ONE digit and listen for your crosstalk. You might find one bad phone and not have to rewire the whole place.

good luck

Daron J. Wilson, RCDD