sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring two line/4 conductor jack to fax machine question

I have a four conductor surface mount wall phone jack with two lines wired into it.

I want to use a fax machine that has a four conductor jack on the backside of it.

Obviously, a four wire cable with plugs on each end will fit up mechanically.

Will that work electrically to put my fax machine on one or the other of the two lines?

Or, do I need to do something else?

Is your fax machine a single line, or two line model?

If it's a single line model you will only have access to the line on the middle two pins of the jack. If you only need one line at the fax machine and you don't care which of the two you get, then yes, this will work just fine.

Great. I can live with that. And, it's a single line fax machine.

Just out of curiosity, if it did make a difference which of the two lines gets to the fax, could I just swap the pair inside the wall jack if the wrong line comes up to the fax?

Matter of fact, does it make any difference which pair of line wires goes to which set of jack terminals?

Yes, you can swap the pairs. Red and Green are line one, middle pair. Black & Yellow are line 2.
Mark

Is your fax machine on line 2? If so, go to radio shack and get a Line1/Line2 splitter that simply plugs into the jack. You can then plug your phone into Line1 and your fax into Line2.

Thanks guys. Now I think I'm ready to get my trusty screwdriver out and gleefully jump into jack rewiring, if necessary, and have some chance of knowing what I'm doing.

Let me come back to something Mark said about the middle pair being line one.

By this, do you mean the middle two of the four wires in the plug? I've noticed that some of the plugs have only two inside conductors hooked up, and others have all four conductors hooked up.

I assume the ones with only the two middle conductors are a single line phone setup, and the ones with four conductors are the two line setups.

Correct :thumb:

Super. Thanks again to all.