Cat 5 cable - finding the correct end!

[Deansplit]

Hi

Is there a way of testing with a meter to find the corresponding end of a Cat 5 cable? I thought I had it right, and have connected it up right to the socket but have no connection. Seem to think there's a way of joining 2 wires then measuring resistance?

Thanks

 

[crystal ball]

Wire mapper and/or cable tracer

 

[Nozzle]

Trial and error and using the bleeper on your DVM. Take one cable, at one end connect two of the cores together. At the other end, use your DVM on continuity and keep buzzing out the pairs until you find one pair that buzzes. Once you've found it, the particular cable you're holding corresponds to the one with the twist in at the other end.

Nozzle

 

[securespark]

http://www.maplin.co.uk/p/lan-network-cable-tester-n59by

 

[Deansplit]

Trial and error and using the bleeper on your DVM. Take one cable, at one end connect two of the cores together. At the other end, use your DVM on continuity and keep buzzing out the pairs until you find one pair that buzzes. Once you've found it, the particular cable you're holding corresponds to the one with the twist in at the other end.

Nozzle

That's the answer i was looking for - knew there was something like that, thanks. So basically connect any 2 cores at the router end and how do I 'buzz' out the other end? What setting do I need the DVM on? The plug's on the router end, does that mean I have to cut it off? :/

 

[Nozzle]

If it already has plugs on both ends then you just plug equipment in and look for the link light. You can still use the DVM probes on the small contacts of the plug. Use the DVM in continuity mode - (usually on the resistance section) and look for the musical note. They're all different though, I can tell you exactly how to use it.

Nozzle

 

[securespark]

You could use the kit I posted the link to. Use a patch lead with one plug off or make a lead from a short length of cable with a plug on one end.

 

[Deansplit]

If it already has plugs on both ends then you just plug equipment in and look for the link light. You can still use the DVM probes on the small contacts of the plug. Use the DVM in continuity mode - (usually on the resistance section) and look for the musical note. They're all different though, I can tell you exactly how to use it.

Nozzle

Hi, no there's a plug on the internet end and I've connected what I think is that other end to the socket but no luck. I've checked and triple checked the order of cores and connections. So apart from connecting each end at the various sockets I don't know which is the correct one.

 

[endecotp]

Is enough of the cable exposed to see the printing on it? They have lengths printed on them.

 

[Chri5]

Say you have four cables, at the open end twist pair one on cable one, twist pair two on the second, pair 3 on the thrid and pair four on the fourth.

Either a continuity function on a meter, a adapted touch with two wires poking out or even a old door bell.

Go to the plug ends, then touch the two wires of your 'tester' on every plug pin pair one. The one that buzzes, turns the lamp on has now been identified. Repeat across each cable and you will find pair 2, 3 and 4.

Mark the feckers with a sharpie, and repeat it you have more than 4 un identified cables.

Pair colours are w/blue, w/orange, w/green, w/brown. All plugs are clear so you should be able to see the layout of pairs in a rj45 plug. If you cant print off a picture via google.

 

[davelx]

If you cant print off a picture via google.

Bearing in mind that there are two ways they could be wired, EIA/TIA 568A, or 568B. Premise wiring should be 568B at both ends (crossover cables are wired 568A one end and 568B the other)

 

[endecotp]

Premise wiring should be 568B at both ends

Says who?

 

[securespark]

Hold on. If there's going to be a scrap, let me get some popcorn.

 

[motorbiking]

a network tester like the above costs about £3 on ebay.

you plug one end at each end and the lights light up. it will scroll in sequence and will show if you have an A to B mix up.

There is no reason to choose A over B as long as you are consistent

 

[davelx]

Says who?

Lots of sources ( you can search them ou for yourself if you are that bothered). It seems to be what has commonly been adopted in all datacentres and offices I've been involved with, whatever the written standards say, and I know there is some debate in this area. ICBA to get into an argument about it, it's not going to stop the bombing of Alepo.

All the OP needs to know is that there are two possible ways the connectors could be wire and that they might not be the same at both ends.