atcomsystems.ca/forum Forums General General Telephone & Systems Information Need general phone help

Not an ESI question, but I know there are some good resources here.

I have a block of about 60 POTS lines that I need to go through to see what is in use. This group has had lots of modems, faxes and other devices in the past, but they have both moved on to better technology and moved the people around the building multiple times.

I don't have a Sidekick, nor do I know how to use one even if I borrowed one. I pretty sure it measures resistance in Ohms accross the pair to detect a short, open, or an instrument on the far end of the pair..

If I were to use my multi-meter to try and do this, do any of the tip and ring guys know what measurement I'm looking for to detect an instrument on the other end of the pair? I'm also pretty sure I measure the pair with the line removed, but I just wanted to verify it.

Thanks in advance

By far, the easiest way to test these lines is to place calls to each number. At least that gives you a clue as to whether or not each one is being used for something. You'll need to allow at least ten ring cycles to be sure since some devices aren't set to answer right away. You have to be careful about alarm lines, elevator phones, etc.

You can use a standard multi-meter to test toward the station end of the wiring on the capacitance scale. Wiring will always cause the needle to kick even with nothing on it, but when there is a ringer load, it kicks more. By reversing the polarity of your leads after testing, you'll get a second chance to measure the kick.

I'm going to move this thread to the "general" category where you're likely to get more attention and replies.

If you get a DPDT switch from Radio Shack, you can wire it up to provide the polarity reversal without having to swap the leads. As long as you have a high resistance scale (like Rx10Meg), an analog multimeter works OK.

how much resistance am I looking at on a pair with an instrument on it vesus an open pair?

That would depend on length of pair and if there is a coil or winding on the end of it, like a standard bell.

I keep a rig like Tommy describes handy just for such issues.

Experiment, get a Single Line phone and look "OUT" at it with the "TOGGLING" Ohmeter. Then, look at a spool of wire.

When you do that a few times, you will get a feel for what is what.

I'd be willing to bet you won't find many modems or fax machines, just empty wire.

You can use this method to determine if there is a station at the end of any line. (or a station anywhere across a line)

Take the meter and go from each side in turn (first the tip, then the ring) to ground. The kick will be the same on each side to ground.

Now measure ACROSS the pair (from tip to ring).

On a line with NO ringer or equivalent termination, the kick across the pair will be LESS than either the tip to ground or the ring to ground measurement.

On a line with a ringer, the kick across the pair will be MORE than either of the sides to ground.

Hope this helps.

i suggest you invest in a sidekick, they dont issue them to us guys for nothing. they are the best multi-meter hands down in my opinion. they come with an instruction manual and there is plenty of literature training availible on the web. just google sidekick training. ive seen them on ebay for under 200 dollars.
on the 10k scale with the t&r leads connected across the pair on the station side of the cable pair, kick the pair by using the REV key, the needle should slam to the right, to determine roughly how many sets( worked better in the old days before all the different crap hooked to phone lines)move the dial to the 1k setting and hit the reverse key again, if it kicks 20 points you should have 2 sets, 30 points, 3 sets and so on.

Thanks for your help, guys. I'll be working on this project this week. I'll let you know how it turns out.