None of the network cable I cut is working

[fafster]

There's something odd going on that I'm having trouble getting to the bottom of. Every single cable I'm cutting doesn't work. I've cut hundreds of cables in the past, so I'm pretty sure it's not me being inept.

 

I'll run through what I'm doing so that anyone else can jump in and call me thick:

 

Cut wire to appropriate length.

Trim half an inch of outer sheath off the end.

Split cables into sequence: w-o, o, w-g, b, w-b, g, w-b, b

Straighten up wires and trim off a few mm of the end so they're all the same length.

Feed into connector and after a final check to see that the cables are in order, crimp.

 

I'm experiencing different symptoms. Some computers will pick and drop the connection continuously, others won't see anything at all. Using a desktop switch (we don't have proper testers) the cables will sometimes light up, and other times not.

 

Am I missing something glaringly obvious?

[matt40k]

Assuming the cable looks ok after crimping. Does the crimp appear to be crimping correctly? If so, you might have got a bad batch of connectors. The cables sequence isn't really important, so long as you get it the same both ends.

 

I assume it's not over 100m (lol if it was), not a faulty switch\NIC. If your just using a switch, have to tried using the cable between a computer and a switch. Switch to switch could cause loopback and the ports SHOULD be disabled.

[ninjabeaver]

At my old job, my crimping tool where it pushed the metal pins through the cables had bent out slightly causing the pins either to not push through at all or just bend.

 

Might be worth investing in a new crimp tool and get yourself a little tester as well. I've seen them quite cheap now for a basic lights on off tester.

 

Cabling order is spot on as you know.

 

 

EDIT:- http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170234930609&cguid=292734be11d0a0e204e269a2fff5ba0d Cheap Tester

[plexer]

Buy proper certified patch leads problem solved.

 

Ben

[dirtydog]

Ive had this before, I went back and crimped them extra hard and problem solved.

[fafster]

I think I may have to purchase a load of patch leads.

 

Cheers for the replies all. The connectors are all new, though I've tried both old and new cable. It's either the crimping tool or connectors, methinks.

[tech_guy]

Yes, we had a silmilar issue with a crimping tool; unless you squeezed it really hard you never got a good connection. Binned it and got a new one and the problem was solved.

[plexer]

I presume you are crimping stranded cable and not solid core?

 

Ben

[contink]

Think I might know what it is...

 

There's two different types of RJ45 plugs that you can get... A bog standard one and the AMC (think that's the brand).. They use slightly different crimping dies and won't work properly with the other plugs ones unless you're very lucky.

 

I hit the same problem with an order of plugs from toolstation that were AMC and I didn't know about the difference until I started doing some searching and then looked very carefully at the plugs for any ID markings.

 

My solution was to buy a two crimpers with interchangeable heads for the different types and then just grab both heads and one crimper. Works great now.

 

I'd definitely recommend getting a cheap (£8) cable tester though from somewhere like toolstation, screwfix or even eBay... it makes you're life sooo much easier with stuff like this.

[DSapseid]

Yes i had this as well and it was the crimping tool that was busted.

[Butuz]

I gave up mass crimping several years ago. Patch cables are so cheaop now that it simply was not worth my time sitting there for an hour just crimping and cutting and trimming.

 

I still do the odd crimp if I need a really long patch cable or something out of the ordinary. But 0.5 - 10m gets bought.

[SpuffMonkey]

Yep - buy them. Well worth getting a decent tester - we bought a NetCat Pro and for the price its excellent - even tells you the distance to the break.

[james_yale]

If you suspect your crimp tool you can try getting a small flat head screw driver and (lightly) hammering each of the pins on the RJ45 to ensure it has penetrated each conductor of the CAT5.

 

And the order is very important, simply matching both ends will make for extremely unreliable patch leads.

[matt40k]

And the order is very important, simply matching both ends will make for extremely unreliable patch leads.

 

 

Perhaps you could explain. All the pairs are the same diameter, same material etc. Otherwise there would be more types of cable. The simple reason why you use a standard coding is the same as why you use standards.

[plexer]

It's to do with crosstalk on pairs.

 

How to wire Ethernet Cables

 

Ben

[james_yale]

Perhaps you could explain. All the pairs are the same diameter, same material etc. Otherwise there would be more types of cable. The simple reason why you use a standard coding is the same as why you use standards.

 

The order for the wires is specified so that the twisted pairs are used as transmission pairs on the cable. I'll be brief here because wikipedia is more eloquent: twisted pair cabling works by sending 2 signals, 180 degrees out of phase over each wire of the pair this enables interference (happens equally to each wire) to be eliminated at the receiver end.

 

For 10/100Base-T operation the green and orange pairs are used, for gigabit operation all four are. If you don't transmit the differential signal over each wire of the pair then the summing at the other end won't work out.

 

As for how this affects the cable order at the plug end, 10/100Base-T use pins 1,2,3 and 6 which is o-w, o, g-w, and g according to T568A/B.

 

Twisted pair - Wikipedia, the free encyclopedia

Edited November 6, 2008 by james_yale