help with making ethernet cable

adbp1 · 28 Jul 2008 at 23:56

hi all, i have just moved the router so i needed to make an extra long cable, i have followed guides and i believe done the correct cable arrangement but my pc still tells me no network connected.

from left to right: brown, white-brown, green, white-blue, blue, white-green, orange, white-orange.

with the click tab facing away and exact same on other end, all the guides i read or watch tell me to use tester but i dont have one !!!

ive only got 2 connectors left to try again so has anyone got any tips or ideas what i might be doing wrong?

thanks ali

MikeHiow · 29 Jul 2008 at 00:31

I've always used

White-Orange, Orange, White-Green, Blue, White-Blue, Green, White-Brown, Brown

(The above order, is starting from pin one,on your left, if you have the connector upside down, and facing away from you.)

Although, if you have the same both ends, you'd be unlucky to see no connectivity at all, regardless of wiring order.

Have you made sure the cable is pushed right in, all cores the same length and reaching the end of the connector? Also check you have crimped them properly. I have no idea about the RJ45 plugs you have, but the ones I used always clicked once the pin broke the wire.

Do you not have a muti-meter to check continuity? You can pick them up from as little as £5.

K.C. Leblanc · 29 Jul 2008 at 00:57

Google image search "Cat 5 wiring". Some of the diagrams will list two layout, use the same at both ends.

It's important to have a pair at each edge and then a pair with another pair in the middle of it. I've used a cable with 4 pairs next to each other and it didn't work.

adbp1 · 29 Jul 2008 at 01:10

after taking out the cable from one end i can see that the pins of the connector have not pierced the wire fully, my multi meter had dead battery might have to go buy one tomorrow!!
will go buy some decent rj45's at same time.

thanks ali

Rykaro · 7 Aug 2008 at 23:59

To be honest, the colour coding is irrelevant so long as you use the same colours on the same pins at both ends, unless you want to conform to a standard such as EIA/TIA 568A or B.

Deaco · 8 Aug 2008 at 08:18

Rykaro said:
To be honest, the colour coding is irrelevant so long as you use the same colours on the same pins at both ends, unless you want to conform to a standard such as EIA/TIA 568A or B.

Not true, each pair has different twist rate pairs 7 and 8 (brown) have a lot less twists as they are mainly a redundant pair mainly for power in PoE setups. Where as pairs 1 and 2 (orange) have a lot tighter twists. Depending on the length this may cause issues - also depends on what speeds you are running at.

Rykaro · 9 Aug 2008 at 18:39

The number of twists in Cat5 and 5e cable per meter isn't going to cause any issues unless you're pushing 125 meters. It's also the first I've heard that the twist rate is different on different pairs. It would actually cost more to manufacture cable with different twist rates on different pairs because you'd need to have the machinery built to account for that rather than the same twist rate on all pairs.

I have a 40 meter run from my ADSL Router to my firewall in the attic which I've not standardised and I have ZERO issues with so I would disagree with your statement that you will encounter issues if you don't conform to standards.

Of course...my sceptisim would be laid aside if you've, say, counted the twists per meter of the pairs in Cat5 cable as proof...but that would be very sad

Sone · 10 Aug 2008 at 19:48

Rykaro said:
The number of twists in Cat5 and 5e cable per meter isn't going to cause any issues unless you're pushing 125 meters. It's also the first I've heard that the twist rate is different on different pairs. It would actually cost more to manufacture cable with different twist rates on different pairs because you'd need to have the machinery built to account for that rather than the same twist rate on all pairs.

We have cables over 200 metres (used to run dumb terminals off them at 9600) and they still work fine at 100mbit.

dave-lew99 · 10 Aug 2008 at 21:41

Keeping the wiring in the right order is important (not due to 'twist rate' which really, is rubbish) but you have to keep the pairs together otherwise you negate the whole point of using a balanced/differential system.

The Tx+ and Tx- must be on the same pair plus Rx+ and Rx- on it's own pair. For gigabit all 4 pairs are used.

Proper PoE does not use a spare pair, it is capacitively decoupled in a similar manner to 'phantom' power systems used in professional audio applications. I have seen non-standards PoE which used a spare pair and only supplied 5 or 12 volts instead of the mandated 48v.

Deaco · 1 Sep 2008 at 09:33

Rykaro said:
The number of twists in Cat5 and 5e cable per meter isn't going to cause any issues unless you're pushing 125 meters.

...

Of course...my sceptisim would be laid aside if you've, say, counted the twists per meter of the pairs in Cat5 cable as proof...but that would be very sad

Having worked with network cable for 10 years, I don't need to count it.. on the cable we use you can quite clearly see that some pair have more twists than others, so not particularly sad.

Really it depends on a lot of things, running gigabit near a leaky mains over 100 metres and you may struggle. It all depends but saying that I have seen some shocking installs that have sorta worked but never passed Cat 5e certification, installed by people who think they know what they are doing.