So... here's the sp. I've bought a house and all the rooms have Cat 5 cable already in place. The wall sockets are labelled 568B on the inside and, in order, the wire pairs are BLUE/ORANGE/GREEN/BROWN. All the cable runs go back to the attic but the previous owner has removed the patch panel and so all the cables are now unterminated. I believe that ethernet uses the 2nd and 3rd wire pairs so, for 568B, pins 1,2,3 and 6 should be w/o,o,w/g and g. Pins 4,5,7 and 8 should be bl,w/bl,w/br and br.
I'm cheap and I don't want to pay for a new patch panel.
What I want to do is simply attach RJ45 plugs to the unterminated ends and plug them into a cheap switch but... if I wire the plug to either the 568B or 568A pattern it fails. I know that the switch is sound as I've tested it working using cables I made up - which also suggests I'm using the crimps correctly - so what am I doing wrong?
For my own installation I've used only Krone or Molex stuff (using transitions and patch panels and know what I've got.
However, I have seen cheap wrongly manufactured outlets and patch panels where the connector labelling is simply wrong - being neither T568-A nor T568-B. Where wiring was done using patch panels and outlets from the same manufacturer, all was well - it was consistently wrong.
This is one possiblility.
A second is that the previous owner has wired incorrectly.
Thirdly, when you crimped the connectors did you do them the right way round? This is a common mistake.
Looking at the RJ-45 with the clip facing away from you, Brown is always on the right, and pin 1 is on the left. Again you can get this consistently wrong and a cable with both connectors wrong, still works.
Fourth possibility is that the one or more of the wires at the outlet socket is not punched down properly or that there is a break in the cable. Any of the four wires being broken or shorted will cause the cable not to work.
To check these latter points, you need to do a continuity and correct connection test.
You can either do this quickly and quite cheaply by using a simple LAN tester like Maplin N75CC £12.99, N59BY £19.99, or A35CJ £19.99 or any one of a number of others.
These work by having one box which puts a DC voltage on each pair in sequence and has a second box with 4 or 8 LEDs which will flash in sequence if all is correct; or flash out of order, red rather than green or with missing or more than one LED in the sequence according to the problem. You attach one box at one end and the other at the opposite end and cable problems become quick to find.
You can, of course, make one:
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I suspect that by the time you had bought the bits, the component cost would be not far short of the £12.99 to buy one.
Alternatively, if you can get a helper willing to spend a lot of time on this, you could run a single wire from your location to where they are at the other end and have them connect it to each wire in turn while you use a continuity tester, one wire at a time. That would give you continuity and position confirmation, but not shorts without testing every combination.
Having said all of this, since a 24way patch panel can be obtained for as little as £25, the exercise of titting around making up cables seems a huge waste of time. You don't have to buy the £100 Krone ones.
Either way, I think that a LAN tester would save a lot of frustration.
I found plugs that specifically said they were suitable for use on solid core cable (some are designed for stranded only, and will potentially cut the conductor on solid core). I then used a short length of heatshrink (handy place to write where the cable runs to) and a snag boot to give some strain/radius relief to the cable/plug arrangement. Careful arrangement of the conductors, a sharp pair of scissors and a crimper borrowed from work (I got all the other bits from CPC) made it a remarkably quick task.
Well I'd check that the cables have basic contunuity (see below) and that the sockets are correctly wired to one standard or the other, or some other arbitary fashion. Whatever it is you 'just' need to bring the wiring out in the same way at the plug, which can be a bit mind turning unless you actually stare into the socket bit rather than looking at the back plate.
To help me make sure things were going well as I went I made a little gadget consisting of a plug with solid core crimped in and then each pair (orange, blue,, etc) twisted together (which I think remains valid even if a non-standard scheme has been used at the sockets). I plugged this into each socket as I crimped the other end up, and immediately after crimping it put a spare socket onto the plug. I then used the IDC terminals on the back of the socket and a multimeter to ensure each pair was connected to itself, and not to any other pair.
I was pleasantly surprised to get absolutely no problems as I did this except for one wire which I'd punched down badly at the far end in the kitchen, so was actually able to address 'other end' problems too. Everyhing has been working fine for 4 years, and I recently finally switched from 10Mbs to 100Mbs (which I though might show up any latent issues).
Subsequent to doing the above I've inherited an unused genuine Krone
24-way patch panel, but its quite a cumbersome beastie. One advantage of the above is the compact arrangement of things under the stairs. The Krone would take up a lot more space. If ever anything broke I'd probably strip one of the 3 eight way sub-units in it to make things more compact, or simply buy something suitable from eBay. Lesser-/no-name items are darned cheap, albeit at the risk of not being very good quality.
1 - OR\WHT
2 - OR
3 - GRN\WHT
4 - BLUE
5 - BLUE\WHT
6 - GREEN
7 - BRN\WHT
8 - BRN
Wiring them in sequential 'pairs' is neither TIA568A or 'B so that's why neither work.
You've lost me on that bit, TIA568B ethernet cabling uses pairs 1 and
2, which is ORANGE amd GREEN.
Your problem, not mine. ;) My patch panel works superbly, along with the voice panel, rack and switch.
Ask Geoff, apparently it's so simple anyone can do it without needing to know what they're doing. Either his theory is wrong or you're really really thick. Chances are, it's not as easy as everyone seems to think.
;-) yup, buy a cheap patch panel and use pre made patch leads - life is to short otherwise!
Even consistently wrong can be dodgy since you can end up with all the right connections made but not using the matching halves of the twisted pairs. So you end up with wiring that may run fine at 10mbps and fail at
You don't want some 'arbitrary fashion' just to maintain continuity. They need, at least, to be wired in pairs. So it's just as easy to use the recommended ones.
I think he means that's how the pairs are shown on the punch down of the wall outlet. These can often be organised in a different way depending how the PCB tracks run (if a PCB is used) for convenience of connecting. However, I have seen some that were wrongly coded.
He went on to say:
"for 568B, pins 1,2,3 and 6 should be w/o,o,w/g and g. Pins 4,5,7 and 8 should be bl,w/bl,w/br and br."
No, the original words did get a bit confused. I was making the possibly rash assumption that even if someone had gone off piste regarding using a true standard they would have at least kept each pair's integrity.
Assuming pairs have been used in this way I was suggesting it may be as well to leave them as they are at the soecket end. Personally I'd re-punch them to be standard if there was enough slack to pull them and trim them.
On or around Sun, 23 Oct 2005 12:54:51 +0100, Andy Hall mused:
Thankyou, but I am fully aware of what an RJ45 plug is and how it all goes together. The pin order is the same for plugs and sockets though. I won't insult you by posting pictures. :P
Completely irrelevant then as the outlets could be any make and be in any order.
I know see what the OP was trying to get at and I obviously misread\interpreted part of the post.
The summary is still the same though,the wiring is wrong somewhere, it's not exactly difficult to make sure the wires are in the correct terminals at each end.
If they are wired sequentially, without the "split" of the green-green/white pair, you have the data travelling down wires that are not part of a twisted pair. This will be OK at DC with a voltmeter testing pin1 to pin1, etc. and may be OK for low speed Ethernet but will not work for 100Mbps. (OK you might get away with it, depending on the choice of interface cards and cable location but it is a definite installation misconfiguration.)
Years ago we had the first attempt at data wiring in a factory done by a someone who hadn't done Ethernet before but knew telephones... They simply wired the pairs 1/2,
3/4, 5/6 & 7/8. It buzzed out fine and worked at 10Mbps but when things were upgraded to 10/100MBPS auto ranging interfaces, it all fell apart.
My recommendation is to wire things up using the correct sequence, as shown by Lurch above, and terminate your fixed wiring on RJ45 wall sockets, e.g. see the bottom of:
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can then use patch cables (same page or shop around - even B&Q...) to make a real neat installation that will work, won't need any crimp tools (the cheap ones can be difficult to use) and will be easy to maintain - at least mine is. Since you won't have used solid cable in the wrong place (terminated to mobile crimp plugs) you won't have failures due to flexing of the solid cables and the possibility of connections made with the wrong type of crimps. The cheaper plugs are for stranded wires since, if they are used with solid, fixed wire the pins will bend if asked to pierce the solid wire.
Probably using plugs designed (as most are) only for stranded cable. These cut (or miss) the solid cored on fixed cable and if they don't fail immediately often do some time later. Far better to invest in a patch panel. At a bit over a pound a socket it isn't as if they are expensive :-).
Either you've got the colours mixed up, or else the previous installer has. You'll have to pull off a few wallplates and find their allocation, and then simply copy it in the attic.
Re wiring solid cable straight to crimp plugs, it's poor practice but it generally works ok. I've done it in our small home network (1 server, 4 desktops, 1 laptop, 1 WAP, 1 router, 2 switches) and we've had no problems after 2yrs. At some time in the future I'll probably wire it up properly through a patch panel, probably when we move to gigabit speed.
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