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Dead phone cable troubleshooting advice

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ECDerek

ECDerek

IS-IT--Management
Nov 4, 2013
45
CA
I'm trying to troubleshoot a bad phone line and I'd like to know if I've tracked down the problem.

The situation is that I'm adding a phone to an office that was cabled 3 years ago with the rest of the office. At no point has this line been in use before trying to add this new phone. The phone is not connecting to the phone system (Avaya IP Office 500 V2--the card led doesn't light and the phone doesn't get power).

I've tested the phone, and the cable to the phone from the jack, and I've tested that the cable from the patch panel to the port are all good. What I don't have is a line tester, so I made a cable I could plug into the patch panel and loop together each pair of wires. At the other end I just used a battery/resistor/led to check for conductivity. 3 of the 4 pairs of wires are good, but one pair is bad. Is this bad pair the (probable) reason for my line being dead?

I'm not a phone guy and I don't know much about how these work, so my only hesitation is whether or not this pair is a required pair. Thoughts? Suggestions for further testing? We're pretty budget-conscious here, so I'm trying to do all the testing I can before we call in the cabling techs.

(Of course, I realize the limitations of my crude test, but it's fine for basic conductivity, which it seems to have worked well for.)
 
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You might have better luck posting in the Avaya IP Office forum....
What type of phone are you working with, digital or IP?
 
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They're digital. I posted here because I'm pretty sure it's a cabling issue; the unit itself is working properly. The (to the best of my knowledge) problem is isolated to this cable.
 
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Typically digital phones work off the blue pair, but I do not know Avaya office systems at all. Seems strange that you have Avaya IP system and are running Digital sets on it though - as I said I do not know Avaya office systems though.
 
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IP Office digital phones also use the Blue pair. The blue pair should be the 2 center pins/pins 4,5 if using an ethernet patch cord.
It could be that there is an improper termination either on the patch panel or on the jack.
 
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vtphoneguy, do you mean they exclusively use the blue pair, or both the blue and green pair?
 
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Exclusively one pair....blue...assuming that both ends of the cable have been properly terminated.
 
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I would put an analog dial tone on the pair you are attempting to use. If you get no DT I would go with another pair. If still no DT I'd say your pinouts are incorrect and you are not on pins 5&4 (white/blue). Once you get a dialtone, it will also accept the digital port you are attempting to connect.


Always look out for the next tech. because one day it will be you!
 
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Pinouts are correct; 5&4, white/blue. I don't know what you mean by putting an analog DT on the pair (I mean I understand theoretically what you mean, but don't know how to go about it), but before I chase that down I'm waiting on some info from the IP Office forum. I've got a call in to the tech but I want to make sure it's not some kind of software config that I've overlooked.
 
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Consensus on the IP Office forum is it's a cable/termination issue. It's definitely not the phone, the other cables, or the IP Office. I'm keeping my service call. I'll update when they've finished for closure.
 
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No problem, EC. I was just trying to rule out the wiring. Jacks go bad, too, you know. Could be change the jack and problem solved. Defective or bent pins inside.

Always look out for the next tech. because one day it will be you!
 
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The jack was terminated incorrectly. The pairs were all correct, but it was a newer jack with a compression cap that is maybe supposed to eliminate the need for punching down the wires, but didn't work in this case. Why it wasn't tested at install I can't say. Anyway, that was the issue. Thanks for all your help!

Here's the jack in question:
 
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I knew it was the jack! Just kidding......glad you have it figured.

Always look out for the next tech. because one day it will be you!
 
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