0

I wired up a ~40m long CAT6 cable following T568B pinout.

According to my tester, pins #6 and #8 are not functional.

I have re-wired both ends several times to make sure it's not my poor crimping; looks like the cable must have some damage.

I would prefer to not have to replace the cable because it's inside walls and ceilings (which is probably where it sustained damage, if any).

Is this usable?

Improve this question
2
  • 2
    Unfortunately, you need to replace the cable. Also, remember is is a Category-6 cable, not an ethernet cable, because it can be used for applications other than ethernet. Even experienced cable installers can have problems installing Catefory-6 and above cables that pass the category text suite, which requires much more than a simple wiremap. This answer explains about the basic required tests, and it does not seem you have the proper test equipment.
    – Ron Maupin ♦
    Jan 13, 2022 at 1:10
  • 1
    In any case, if the cable installer did not also run a pull string, you can use the bad cable as a pull string, but be sure to run a pull string with it. Exceeding the maximum pull tension or minimum bend radius can permanently damage the cable. Your company should hire a certified installer who will give you a test. report on each cable. Using unqualified installers can end up costing more in the long run.
    – Ron Maupin ♦
    Jan 13, 2022 at 1:55

2 Answers 2

Reset to default
1

Generally, you cannot repair Cat 5/6/7/8 cabling other than at termination, and only when there enough slack left.

You could use a time-domain reflectometer to locate the fault - hopefully at one end -, remove the faulty segment and re-terminate.

If you decide to replace the cable, heed Ron's warning and hire a skilled installer. If maximum pull tension or minimum bend radius are not observed at all times, a cable can easily get permanently damaged. Also, a deployment should always be certified using a proper tester, so you know the installation is reliable.

Improve this answer
2
  • 1
    Many testers have a length mode that might help locate the break. (it's capacitance, not TDR)
    – Ricky
    Jan 13, 2022 at 10:13
  • @ricky AFAIK, capacitance-based measurement is fairly inaccurate.
    – Zac67 ♦
    Jan 13, 2022 at 11:30
0

If you are desperate to get some kind of link up without replacing the cable you can probably get a 100 megabit link working by re-wiring the cable in a non-standard way so that the good pairs are on the pins used by 100 megabit Ethernet.

It's not a great practice though.

Improve this answer

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.