Sanity Check: Is my CAT5e cable probably bad, or do I just need different connectors?

Question

I'm working with a small company, and since I'm the only one with even a half-ounce of network infrastructure experience I've got the job of wiring up our network. So please forgive my newbie-ness.

Needed to run some CAT5e cable up the outside wall from the first floor to the second floor, to add a wireless access point upstairs -- the floors must be thick concrete or something, because the signal from floor to floor is pathetic.

I had this cable: http://tinyurl.com/bl349f8

And these connectors, which I now realize were not the recommended ones (they're designed for flat cable): http://tinyurl.com/a94ttou

Anyway, I just spent a bunch of time on a ladder stringing up the cable, snipped off one end to run it through the hole I drilled in the wall, and then attached one of the abovementioned RJ45 connectors to the end. Plugged one end into the router, the other end into my mac, and got no signal. Snipped the end and tried 2 more times, and am absolutely positive I've attached the connector properly. I stupidly hadn't tested the cable before stringing it up, so I don't know whether the cable itself is faulty.

So finally to my actual question. I know the connectors I bought aren't really the correct ones. But I don't know if they're wrong in the sense that they just aren't ideal, or if they're wrong in the sense that they won't work. If the latter, OK, easy fix, just get the right connector. If they SHOULD work OK, then that means I probably have to re-run the cable, which I really don't want to have to do.

So... given the above, is it probably just that I need the proper connector, or is the cable likely bad?

Thanks!

UPDATE:

The problem is that I'm a moron and switched the green/white and blue/white wires.

Sorry to waste everyone's time on that!

Solution 1

If you just cut one end off a manufacture cable and then aligned the wires as you noted (brown, brown/white, green, green/white, blue, blue/white, orange, orange/white) you likely have a problem with the wire order.

There are two standards for cabling:

• T568A: green/white, green, orange/white, blue, blue/white, orange, brown/white, brown
• T568B: orange/white, orange, green/white, blue, blue/white, green, brown/white, brown

I would double check your manufactured end to ensure what the order is, and match that pattern on your re-terminated end.

As others mentioned, you can check your termination and cable with a cable tester. This should tell you if you have miss-wired or have a fault.

Also, if the cable you bought isn't using one of those standards... I wouldn't buy from them again.

Quick Edit

After seeing your comment, I realized that you transcribed the order you put them in, in reverse. Generally, you should read from the side without the clip from left to right.
Doing this would have read (orange/white orange, blue/white, blue, green/white, green, brown/white, brown). Compare to the T568B, and yes it's clear that your problem was with the wiring order.

Solution 2

1. You purchased a manufactured cable and then cut the ends off so that you could fit it through the hole you drilled. Why didn't you drill a hole large enough to fit the connector through?

2. Get a cable tester and test the cable after you crimp new connectors onto it.

3. Take the wireless router to where your MAC is and plug the MAC into it with a different manufactured cable. If it works then you can be pretty confident that your "home made" cable or connectors are the problem. If it doesn't work then you've been chasing a red herring.

Solution 3

It is probably the connectors, particularly the one which you cut and re-terminated. Cables themselves rarely fail unless the cable has been damaged or cut on a snag, etc. Connectors are much more likely to fail-- a gap of less then 1mm can cause a failure.

Get a cable tester. I can almost guarantee you that one of the 8 connections will show up bad.

Comments

[Rex]

The connectors should be are fine. Are you sure you are wiring the correct wires to the correct pins in the connectors? ertyu.org/steven_nikkel/ethernetcables.html

[DanM]

Yes; the wires are in precisely the same order on both ends of the cable (Brown,Brown/White,Green,Green/White,Blue,Blue/White,Orange,‌​Orange/White).

[DanM]

Hrm, actually the order doesn't seem to match the ordering on the page you linked; however they're in exactly the same order on both ends of the cable, so shouldn't that be all that matters?

[HostBits]

did you cut and re-terminate both ends or just the one?

[DanM]

Just the end that I put on myself. Haven't tried re-terminating the end that had a connector on it to begin with.

[Rex]

if you only redid one side, I can almost guarantee with 99.999% probability that the order on the side you did not redo is not the order of the wires you mentioned on the side you did terminate.

[joeqwerty]

@DanM - Definitely not a waste of time. As funny as it sounds this is one of those "D'oh!" moments that we've all had that will make you remember to always double check for proper termination. We learn by doing and we learn best through our mistakes. Cheers.

[DanM]

1: I didn't want an unnecessarily big hole in the wall, and I bought a manufactured cable because I didn't need a ton of cable, 25' was plenty. 2: I'll do that. 3: I did, it's definitely either my cable or connectors that are the problem; I just want to figure out which of those is the problem.

[DanM]

Yep, see update to question... I had a brain lapse and swapped the green/white and blue/white. Works like a charm now.

[Jonathan J]

To clarify for others reading this question: proper pairing is very important. It's not as simple as having the same color order on each end. Each color pair is the + and - of a signal line; if you have the + of a particular signal line on one pair and the - on another pair, the cable will experience crosstalk and be unable to reject interference.