Discuss Ethernet point no internet in the Computer and Networking Forum area at ElectriciansForums.net

robd

Electrician's Arms
Messages
555
Location
East Anglia
Hi all,

On a recent job (electrical) the customer asked if I could add them a point to hard wire his computer to his internet. I put him an ethernet socket at each end, ran a piece of cat 5 in between and terminated with punch tool as per a bt socket. Customer reported not being able to get connected to the internet, they've got a lead out of the router into one socket and a lead into their computer at the other. I went back with a network cable tester so I could check my connections. Plugged into both ends with a long lead in between and it flashed through in sequence all fine.

So from my point of view all looked fine but still no internet. I gave him a long lead which we trailed upstairs and he could get internet fine. The run between sockets is only 10m max. Wondering if anyone could spot anything obvious or had any ideas on what is wrong.

Many thanks
 

Murdoch

Regular EF Member
Messages
25,126
Location
Woking
When you tested your new outlet did you watch the lights on both ends of the lead?

The tester I have can show ok one end, but the other end could be wrong.
 

Loki

Trainee Access
Messages
462
Location
Devon
They haven't plugged in a second adsl filter in series have they? Ive had that before & it stopped internet access


Also when the computer is connected does it get an ip address
 
OP
robd

robd

Electrician's Arms
Messages
555
Location
East Anglia
Thanks plugs I just meant the actual physical process of punching. I followed the colour scheme and did the same at both ends
 

Barnaby Stedman

Regular EF Member
Messages
183
Location
England
are you running the cable out of a LAN port of the router I presume. When you tested straight out of the router did you use the same LAN port?
 

Spoon

Forum Mentor
Messages
7,166
Location
Lancashire
I was going to mention the cables being untwisted...
At least you have lost of slack left. Try terminating the sockets again. Twist the pairs back together as well.
 
OP
robd

robd

Electrician's Arms
Messages
555
Location
East Anglia
When you tested your new outlet did you watch the lights on both ends of the lead?

The tester I have can show ok one end, but the other end could be wrong.
I got a 20m lead with a plug on each end so I could watch them both together, they all flashed through in sequence
 
OP
robd

robd

Electrician's Arms
Messages
555
Location
East Anglia
are you running the cable out of a LAN port of the router I presume. When you tested straight out of the router did you use the same LAN port?
I left him to do that but when I gave him my long lead to try he plugged it in the same port of the router and it worked
 
OP
robd

robd

Electrician's Arms
Messages
555
Location
East Anglia
The orange and white/green look to be in the wrong place.
You've terminated the cat 5 cable incorrectly, you've removed too much of the cable jacket and allowed the core to become untwisted and seperated. The cable jacket should stop as close to the module as possible.
I did do both ends the same wasn't sure what the correct way was as the colours go half and half on two if them. Didn't know you were supposed to not strip too much back or not untwist did by points like that on site for years thought it was neater/easier :(
 

Barnaby Stedman

Regular EF Member
Messages
183
Location
England
ok so it is most likely to be the connections at the sockets. have you seen the issue on his computer - what is the status of the connection on the customers computer?
 
OP
robd

robd

Electrician's Arms
Messages
555
Location
East Anglia
ok so it is most likely to be the connections at the sockets. have you seen the issue on his computer - what is the status of the connection on the customers computer?
No I haven't seen it but the jist I got was it was connected but he couldn't get any internet through it if that makes sense
 

davesparks

Forum Mentor
Messages
12,803
Location
guildford
I did do both ends the same wasn't sure what the correct way was as the colours go half and half on two if them. Didn't know you were supposed to not strip too much back or not untwist did by points like that on site for years thought it was neater/easier :(
Yes, there are the two standards, A and B, that's why there are two different colour schemes labelled. Most people stick to B.

Yes it's easier, whether it's neater or not I'm not sure, but it's wrong.

Did you not take the time to read up on the correct way to terminate the cables before you started installing them? It doesn't take long and it's usually in the instructions that come with modules and patch panels.
 
OP
robd

robd

Electrician's Arms
Messages
555
Location
East Anglia
Didn't see any but there may have been some. In fairness I haven't questioned it until now, haven't done ethernet sockets before but hundreds of bt sockets which I hadn't had any problems with. I do take your points on board though, thankyou. To my mind if the colours match at both ends which they do and I have tested to check they shouldn't stop anything working. But do you think the fact they are untwisted would affect the quality of connection ?

And I only meant neater in a sense that they weren't tight without any slack :)
 

Strima

Electrician's Arms
Messages
3,522
Location
St Neots
Are the patch leads straight through or crossovers?
 

MarkRibbands

Regular EF Member
Messages
302
Location
Malaysia and UK
That socket is wired wrongly. Swap your white/grn and org and it will be sorted. These sockets are confusing - be sure the follow the 'B' column on both sides.
If you're wrong, but consistently wrong, both ends will of course test OK electrically, but the four balanced twisted pairs will be mixed up, affecting the signal.
Also, as others have said, leave the pairs twisted until the last possible point! (And note the frequency of twist in each pair is different. No one said network cabling, for maximum performance, was easy :))
 
OP
robd

robd

Electrician's Arms
Messages
555
Location
East Anglia
That socket is wired wrongly. Swap your white/grn and org and it will be sorted. These sockets are confusing - be sure the follow the 'B' column on both sides.
If you're wrong, but consistently wrong, both ends will of course test OK electrically, but the four balanced twisted pairs will be mixed up, affecting the signal.
Also, as others have said, leave the pairs twisted until the last possible point! (And note the frequency of twist in each pair is different. No one said network cabling, for maximum performance, was easy :))
Thanks mark that's a great explanation, I hadn't thought of that technical side so thankyou
 

Strima

Electrician's Arms
Messages
3,522
Location
St Neots
Not sure Strima, sorry. Customers leads. He is quite a bit cleverer computer wise than me so didn't really question it.
It's not a common issue but it has been known to happen.
 

Murdoch

Regular EF Member
Messages
25,126
Location
Woking
I got a 20m lead with a plug on each end so I could watch them both together, they all flashed through in sequence
That's odd to say the least.
 

happyhippydad

Member
Electrician's Arms
Messages
3,106
Location
Gloucestershire
That socket is wired wrongly. Swap your white/grn and org and it will be sorted. These sockets are confusing - be sure the follow the 'B' column on both sides.
If you're wrong, but consistently wrong, both ends will of course test OK electrically, but the four balanced twisted pairs will be mixed up, affecting the signal.
Also, as others have said, leave the pairs twisted until the last possible point! (And note the frequency of twist in each pair is different. No one said network cabling, for maximum performance, was easy :))
What does this do Mark? How does leaving them twisted together help?
This has been an interesting thread!
 

Spoon

Forum Mentor
Messages
7,166
Location
Lancashire
What does this do Mark? How does leaving them twisted together help?
This has been an interesting thread!
I've been told to leave them twisted as must as possible to reduce noise between pairs.
 

MarkRibbands

Regular EF Member
Messages
302
Location
Malaysia and UK
What does this do Mark? How does leaving them twisted together help?
This has been an interesting thread!
I’m no expert on this, but do like to understand things, and know it’s to do with using a ‘balanced signal’ for low-noise transmission.

On each pair, there is a +ve-going and -ve-going signal, with only the difference them being detected at the far end. If there’s external noise induced on the line, it will usually appear on both wires equally, so remains undetected, as any noise waveform simply provides a signal on both wires equally, not affecting the difference signal. Result: a magically clean signal in a noisy environment!

The twisting reduces cross-talk between pairs in a multi-pair cable. Consider if, due to the extreme proximity of all those little wires, one of a pair might receive a larger crosstalk signal that its partner, it will be unbalanced, affecting the difference signal and so be resolved at the other end as noise, messing up fast data comms.

But if the pairs are twisted, the crosstalk hits one strand first for a bit, then the other for a bit, and so on. Therefore the crosstalk signal is magically applied to each pair’s partner equally. It then ‘looks’ like external noise at the other end and is unresolved.

Twist frequency differs so that different pairs don’t keep crossing at the same points again and again, reducing the cancellation effect.

Clever ennit? :)

I think I've got that essentially right, but if there are any comms network designers on here who know better, please take over!

(cf. Balanced professional microphone cabling using 3-pin XLR connectors and shielded two-core interconnects).
 

Barnaby Stedman

Regular EF Member
Messages
183
Location
England
I’m no expert on this, but do like to understand things, and know it’s to do with using a ‘balanced signal’ for low-noise transmission.

On each pair, there is a +ve-going and -ve-going signal, with only the difference them being detected at the far end. If there’s external noise induced on the line, it will usually appear on both wires equally, so remains undetected, as any noise waveform simply provides a signal on both wires equally, not affecting the difference signal. Result: a magically clean signal in a noisy environment!

The twisting reduces cross-talk between pairs in a multi-pair cable. Consider if, due to the extreme proximity of all those little wires, one of a pair might receive a larger crosstalk signal that its partner, it will be unbalanced, affecting the difference signal and so be resolved at the other end as noise, messing up fast data comms.

But if the pairs are twisted, the crosstalk hits one strand first for a bit, then the other for a bit, and so on. Therefore the crosstalk signal is magically applied to each pair’s partner equally. It then ‘looks’ like external noise at the other end and is unresolved.

Twist frequency differs so that different pairs don’t keep crossing at the same points again and again, reducing the cancellation effect.

Clever ennit? :)

I think I've got that essentially right, but if there are any comms network designers on here who know better, please take over!

(cf. Balanced professional microphone cabling using 3-pin XLR connectors and shielded two-core interconnects).
As being a bit of a data and as it happens live sound guru myself I can only agree with you. What you are saying is dead correct.
 

davesparks

Forum Mentor
Messages
12,803
Location
guildford
haven't done ethernet sockets before but hundreds of bt sockets which I hadn't had any problems with.
To my mind if the colours match at both ends which they do and I have tested to check they shouldn't stop anything working. But do you think the fact they are untwisted would affect the quality of connection ?

And I only meant neater in a sense that they weren't tight without any slack :)
BT sockets are completely different and a bit of untwisting doesn't usually affect them.
The colours need to be in the correct places so that each twisted pair has the correct data signal on it. Mixing the signals between different pairs will likely turn the data into nonsense.

The twisted pairs are used to cancel out interference, being twisted together ensures that both cores receive the same interference so that it can be cancelled out at the receiving end. The number of twists per metre is tightly controlled in the manufacture of the cable for this reason.
 

davesparks

Forum Mentor
Messages
12,803
Location
guildford
haven't done ethernet sockets before but hundreds of bt sockets which I hadn't had any problems with.
To my mind if the colours match at both ends which they do and I have tested to check they shouldn't stop anything working. But do you think the fact they are untwisted would affect the quality of connection ?

And I only meant neater in a sense that they weren't tight without any slack :)
BT sockets are completely different and a bit of untwisting doesn't usually affect them.
The colours need to be in the correct places so that each twisted pair has the correct data signal on it. Mixing the signals between different pairs will likely turn the data into nonsense.

The twisted pairs are used to cancel out interference, being twisted together ensures that both cores receive the same interference so that it can be cancelled out at the receiving end. The number of twists per metre is tightly controlled in the manufacture of the cable for this reason.
 

davesparks

Forum Mentor
Messages
12,803
Location
guildford
This is an excellent example why sparks should not do a network engineers job. (or aerials for that matter).
No it isn't, there are many electricians who have the knowledge and experience to do this correctly.
This is another example of why someone shouldn't just have a go at doing something without seeking the knowledge or training to do it correctly.
 

rsgaz

Regular EF Member
Messages
267
Location
UK
The cable jacket should stop as close to the module as possible.
The jacket should be cable tied to the strain relief loop, hence the tiny little cable tie usually included with the modules.

Untitled.jpg
 
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