Solved Network Jack doesn't work, but plug does.

June 23, 2012 at 13:11:19
Specs: Windows 7
I'm wiring a home for ethernet for a friend, and I have run into a most unusual problem. All wires terminate in the basement as a RJ-45 plug, to be plugged into a switch housed in an old circuit breaker box. The first wire went off without a hitch, the jack works, the plug works, all is right with the world. The router for the home is currently plugged into that outlet so as to give the entire network as we build it internet. The second outlet is giving us problems though. I've fished the wire up the wall as before, and the length of wire is shorter than the first run. When I terminate the end upstairs as a jack, then plug in my laptop, it refuses to connect. It says the network cable is unplugged. If I terminate the cable as a plug, then plug it directly into the laptop, suddenly everything works. I have tried so far 3 different jacks, tested continuity on the jacks, and tested continuity on the wire to the jack pins to make sure the terminal block was working and everything came back green. Any help would be appreciated, otherwise I feel we may have another Chewbacca defense on our hands. This does not make sense, and if it doesn't make sense, you must aquit!

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✔ Best Answer
June 24, 2012 at 18:16:01
Then you may need to use a better testing device. To get the proper quality of the signals the specifications for any cat level is not only the wire but it is length and bends and keeping away from interference. I don't know your exact meter but some meters can have a few to many ohms and still provide a signal. A solid ohm value may have been better to use. That still doesn't help on the ac component of networking. Cat levels are also rated in speeds. Speeds as in frequency. If that fails too much then your nic if set to a high speed may not show correctly.

We still can't be sure of your laptop test. At least get a cheap cable tester or rent a sophisticated one to correct this. An advanced time domain reflectometer (TDR) is one of the best ways to ring a line. Best if it a visual and set to the speed of your system and using termination equal to the theoretical impedance of the wire.

Hang up and live.



#1
June 23, 2012 at 15:02:03
Consider an inexpensive tester for cables. I assume you used a ohm meter for your test. I doubt you need a quality test on the wiring.

http://www.google.com/products/cata...

Hang up and live.


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#2
June 23, 2012 at 18:22:34
The plug us wired left to right, the jack is right to left.

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#3
June 23, 2012 at 21:19:15
For the jack I wired it in identical fashion to the first one. As for testing I used a laptop for the upstairs end, and the switch on the downstairs end. Testing continuity I used a multimeter set to audio continuity to confirm both the jack worked and the terminals were connecting to the wires. I did not test the wire from the downstairs to the upstairs on the continuity test though. I have also rerun a new wire and terminated each end as before, a plug downstairs and a jack upstairs. Same issue.

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Related Solutions

#4
June 24, 2012 at 06:58:20
Which wiring pattern did you use on the plug, T568A or T568B and is the jack wired with the same pattern?

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#5
June 24, 2012 at 09:27:05
T568A for both plug and jack. I have been wiring the whole house with A. I have a new development, a cable about 4 inches tip to tip is able to work, but anything longer fails out of the jack.

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#6
June 24, 2012 at 18:16:01
✔ Best Answer
Then you may need to use a better testing device. To get the proper quality of the signals the specifications for any cat level is not only the wire but it is length and bends and keeping away from interference. I don't know your exact meter but some meters can have a few to many ohms and still provide a signal. A solid ohm value may have been better to use. That still doesn't help on the ac component of networking. Cat levels are also rated in speeds. Speeds as in frequency. If that fails too much then your nic if set to a high speed may not show correctly.

We still can't be sure of your laptop test. At least get a cheap cable tester or rent a sophisticated one to correct this. An advanced time domain reflectometer (TDR) is one of the best ways to ring a line. Best if it a visual and set to the speed of your system and using termination equal to the theoretical impedance of the wire.

Hang up and live.


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#7
June 25, 2012 at 06:28:19
After a lot of banging my head against a wall, a friend of mine stopped by and we started systematic testing. Checked continuity of the cable itself after pulling the whole mess from the wall, which was good. No broken strands at least. Next was testing the cable as network cable. Failed. Redid the ends as T568B, cable worked off of the router. Took the cable to the basement and the switch and tested, worked off the switch. Reran the wire up the wall and retested, cable still worked. I am looking into a decent quality cable tester for the future, as I think most of this could have been avoided if I had something to tell me what I was looking for, as opposed to a binary works/fails test.

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#8
June 25, 2012 at 07:25:00
Those cheap blinking light testers are useless and nobody who's ever done any testing of cables would rely on them. They'll tell you your cable is ok when it isn't.

An ohm meter is not the proper tool either.

However, a good cable tester is going to cost a fair bit of money and since you're only running a few cables the logical thing to do is to call some electrical and/or network cabling companies and ask them how much they'd charge to test and certify how ever many cables you've run.

A little shopping around should get you a reasonable price and you cables will be tested with a tester that can be relied upon. Most importanly, you won't have to shell out hundreds (if not thousands) of dollars and a tester you'll only use the one time.

It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.

***William Henley***


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#9
June 25, 2012 at 08:54:21
Even some higher end testers require the user to know how it works. They may be very sophisticated in how they test but not very user friendly in how it reports.

Hang up and live.


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