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This is a sub-selection from Copper pair loss.
lutful
... of ideas
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join:2005-06-16
Ottawa, ON

lutful to 54067323

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to 54067323

Re: Copper pair loss.

said by 54067323:

if you want to know how a 965 works internally you will have to ask 3M ... 965 is not what I consider a fault locator

You mentioned the 965 earlier. What brand/model do you recommend? FYI all classic "cable fault testers" use Murray/Varley bridge circuits and may also have a tone generator/receiver for opens.

Many newer "cable fault testers" are just a simplified TDR with a numeric display to show distance to very first fault.

Anyway, I am curious what (non-TDR) tool you will personally consider for testing the loop when you have access to ring/tip only from TheMG See Profile residence? That is a very relevant question.
54067323 (banned)
join:2012-09-25
Tuscaloosa, AL

54067323 (banned)

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said by lutful:

You mentioned the 965 earlier. What brand/model do you recommend?

For a POTS or circuits tech shooting the MG's trouble, the 965 DSP is really all that is needed it’s simple and intuitive and will serve a field tech very well for 90% of what they come across.

The 965DSP is literally testing for cavemen.

If the MG's trouble becomes a chronic, then you bring in say a HST-3000 and using that device as a DVOM you can “stress” the pair, the JDSU does this by pulsing the pair with 200+ VDC and measuring the resistance under the higher voltage and the lower voltage, a large difference between the two fails the test, this test also because of cable capacitance has the tendency to fuse open “high opens” making menu selection 2 a lot easier to use..

Anyway, I am curious what (non-TDR) tool you will personally consider for testing the loop when you have access to ring/tip only from TheMG See Profile residence? That is a very relevant question.

That depends, if a tech has CO coverage then the best way is head to head testing, lacking CO coverage, I personally would recommend placing the JDSU FED at the customers prem and going to the CO or the RT’s protector field and doing a full wideband test.

Now that may seem like overkill for a “audio” circuit and I may burn up a few pairs in the process, but I will deliver to the end user a loop that will last.
54067323

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said by lutful:

Many newer "cable fault testers" are just a simplified TDR with a numeric display to show distance to very first fault.

No one in the telecom world has a need for a cable fault tester, because the technician in-the-field has already determined there is a fault in the cable.

What is needed is a cable fault locator, so the location of the “fault” can be determined and cleared…
lutful
... of ideas
Premium Member
join:2005-06-16
Ottawa, ON

1 edit

lutful to 54067323

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to 54067323
said by 54067323:

If the MG's trouble becomes a chronic, then you bring in say a HST-3000 and using that device as a DVOM ...

I am looking back at my original suggestion to TheMG See Profile and your very first response.
said by 54067323:

said by lutful:

You could borrow a JDSU HST-3000 and do a basic TDR check for any high resistance or wet sections.

A TDR would never be my first choice for locating a high resistance splice (high open), the reason being the majority of high opens are single sided events (half opens), that is to say the fault will only be on one side of the pair

So it seems (now) that you did NOT have a problem with me suggesting JDSU HST-3000. You only wanted to make sure that he does not use it's TDR functionality to "check for any high resistance or wet sections" because of your personal experience.

But that opinion is actually contrary to user manuals and support engineers of any non-TDR "fault locator" ... they will happily explain about deficiencies when testing for full/partial opens. I already quoted from 965DSP earlier, you can look up a few others.

You also check EXFO and other "true" TDR user manuals for exact waveforms from all kinds of open faults and decide if you can finally change your personal opinion about TDRs or at least refrain from making comments that are sure to start an argument.