Really struggling with RJ45 connectors.

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HappyHippyDad

HappyHippyDad

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I have fitted RJ45 connectors to either side of a piece of cat5 cable but when I test it on the laptop I get no ethernet connection. I also have a pre-made ethernet cable which works fine so I know it's my home made ethernet cable. I cut the cat5 to 12.5mm and connect both ends the same (i.e s68A)

I have practised this a few times now each with the same result, i.e. it doesn't work.

With a piece of twin and earth I could test for continuity at both ends but how do I test for continuity through an RJ45 connector?

The problems that I can see it as being are the following but I dont know which is the most likely or if there are other problems I missing?

1. Poor quality connectors, not actually making contact in the laptop or router.
2. cat 5 not actually terminated inside RJ45 connector
3. RJ45 Crimping tool not effective which leads to 2 above.

Cheers all.

RJ45.jpg RJ45..jpg RJ45 crimping tool.jpg
 
Last edited:
You can get cheapish network cable testers from ScrewFix.

I suspect it's something simple like you're not pushing the cable fully home. The gold contacts have insulation piercing spikes on them and they aren't that long, so it's entirely possible if the cable isn't fully home, they'll miss.

It's just practice. I've done hundreds over the years and still manage to cock up the odd one.

You can test continuity using your MFT, just make sure your probe tips are nice and sharp so they make good contact with the gold contacts.

Personally I would stick with T568B as that seems to be most common here, although it actually doesn't matter unless you're making a cross-over cable (in which case, one end should be T568A and the other T568B I believe).
 
You can get Cat5/6 continuity testers that will also confirm the order of the conductors. Termination of RJ45 is a right pain. I’ve tried various types and have come to the conclusion that patch panels are the way to go and avoid fitting full stop unless you have to.
 
Agree with SC, its practice and i could not be without my tester. One thing i did notice is that i got a load of Rj45 plugs from wholesaler A and everyone failed, they simply did not line up properly with my crimper, got a load from wholesaler B and they worked perfectly.
You do need to test all 8 wires, even though sometimes not all are used , speedier lines use more cores
 
The cores should generally be wired to the T568 B standard not in the order you have done. See diagram below:
1583680587444.png

Your wires don't look fully inserted, and the contacts look like they might be crimped too far in. I use a Platinum Tools crimper with the matching connectors that allow the wires to protrude through the plug, the crimper trims them to length. Dead easy and very reliable.
 
Wiring a RJ45 is one of my pet hates. You really do need a tester. Don't waste money on an expensive on if you are only doing a few. Mine is similar to THIS Costs a fiver and saves a lot of agro. you can see if the lead is okay straight away. It'll also tell you if you have any crossed.
 
Cheers everyone :)

I took a deep breath and started again, this time it worked!

I'm pretty sure i didn't have the ends long enough. I measured 12.5mm but when you actually push them into the connector they shorten a little and they wern't reaching the metal spikes.
 
Moley said:
Wiring a RJ45 is one of my pet hates. You really do need a tester. Don't waste money on an expensive on if you are only doing a few. Mine is similar to THIS Costs a fiver and saves a lot of agro. you can see if the lead is okay straight away. It'll also tell you if you have any crossed.
Click to expand...
Just bought one! :D
 
The thing I hate to most is unravelling the wires and then trying to straighten them out prior to putting in order. Is there a tool that assists with this?
 
I think I’ve got a spare tester and crimper going begging. Bought a kit myself then obtained another from a retired IT guy.
will look it out and advertise them on here for selling, but I think postage will be as much as the items cost
 
I strongly recommend the wire-through type of plug where all the individual conductors poke out the end of the plug before you crimp down/trim off with the crimper. These have the advantage of not having to be accurate with length and you can easily see the order you've inserted them in.

If you think Cat5 is tricky... wait until you try Cat6 !!
 
There's another thread on here from a while back, but basically the same info-buy good connectors, the pass-thru are so much easier, a decent crimper to match and a cheap tester as linked above.
The cheap testers won't do any kind of "diagnostics" such as used by those who specialise in this type of work, but they are fine for just checking continuity in the connections you make.
 
My suggested method for terminating UTP into closed-end Cat5e connectors:

1. Leave ends too long and untwist as far as jacket.
2. Pinch jacket tightly at end with one hand to stop cores moving about.
3. Pinch cores lightly in a flat row with other hand and pull along them as if combing with your fingers, repeating 3-4 times first giving a curl upwards, then downwards, then straight.
4. Let go of jacket. Pinch fingers together and tuck cores between them in sequence, ensuring they take the straightest route from their position in the jacket without looping around each other.
5. When all in a row pinch jacket again, flex cores up and down once as a flat row to teach them their final positions, then trim to length. They should lie exactly flush and parallel by themselves.
6. Slide row of cores along base of entry channel until sheath is inside clamping zone
7. Visually check sequence and look into end of connector to make sure you can see copper in each position.
8. Keep pinched firmly and push cable into connector while you crimp.

Takes me about 25 seconds, can't remember the last time one didn't work.
Note that some types of RJ45 are designed for solid-core, some for stranded patch and some for both.

Looking at those pics, I agree that the cores are not fully inserted - they should reach to the very end of the channels so that when you look at the end of the connector you can see both the conductor and insulation clearly on each core.

Also as mentioned above, the sequence is wrong. It is not sufficient that each pin at one end is connected to the same pin at the other. Splitting pairs (e.g. swapping one orange with one blue but putting them right at the far end) will completely scramble the transmission as the go and return of each of the four circuits must form a twisted pair to have the correct characteristics.
 
Last edited:
happyhippydad said:
I have fitted RJ45 connectors to either side of a piece of cat5 cable but when I test it on the laptop I get no ethernet connection. I also have a pre-made ethernet cable which works fine so I know it's my home made ethernet cable. I cut the cat5 to 12.5mm and connect both ends the same (i.e s68A)

I have practised this a few times now each with the same result, i.e. it doesn't work.

With a piece of twin and earth I could test for continuity at both ends but how do I test for continuity through an RJ45 connector?

The problems that I can see it as being are the following but I dont know which is the most likely or if there are other problems I missing?

1. Poor quality connectors, not actually making contact in the laptop or router.
2. cat 5 not actually terminated inside RJ45 connector
3. RJ45 Crimping tool not effective which leads to 2 above.

Cheers all.

View attachment 56235 View attachment 56236 View attachment 56237
Click to expand...
I used to do hundreds of them especially patch cables using the B pattern. Eyes have. Got to bad to see the colors so I get my son to do it. You have the right tool
 
FatAlan said:
The thing I hate to most is unravelling the wires and then trying to straighten them out prior to putting in order. Is there a tool that assists with this?
Click to expand...
Use an off cut of the outer sheath and run it down the middle of twisted pairs.
[automerge]1583696953[/automerge]
Just buy pass through connectors and a pass through crimping tool, 10 x faster and accurate.
 
I kept a trimmed perfect template "cable" sample - glued -
to "crimper" storage.
Thru connectors sound so much simpler -to all that preening/re-trimming !
(some crimp tools can add a step to the side of the divider )
(look close with an eye glass !)
 
happyhippydad said:
Just bought one! :D
Click to expand...
Lucien Nunes said:
My suggested method for terminating UTP into closed-end Cat5e connectors:

1. Leave ends too long and untwist as far as jacket.
2. Pinch jacket tightly at end with one hand to stop cores moving about.
3. Pinch cores lightly in a flat row with other hand and pull along them as if combing with your fingers, repeating 3-4 times first giving a curl upwards, then downwards, then straight.
4. Let go of jacket. Pinch fingers together and tuck cores between them in sequence, ensuring they take the straightest route from their position in the jacket without looping around each other.
5. When all in a row pinch jacket again, flex cores up and down once as a flat row to teach them their final positions, then trim to length. They should lie exactly flush and parallel by themselves.
6. Slide row of cores along base of entry channel until sheath is inside clamping zone
7. Visually check sequence and look into end of connector to make sure you can see copper in each position.
8. Keep pinched firmly and push cable into connector while you crimp.

Takes me about 25 seconds, can't remember the last time one didn't work.
Note that some types of RJ45 are designed for solid-core, some for stranded patch and some for both.

Looking at those pics, I agree that the cores are not fully inserted - they should reach to the very end of the channels so that when you look at the end of the connector you can see both the conductor and insulation clearly on each core.

Also as mentioned above, the sequence is wrong. It is not sufficient that each pin at one end is connected to the same pin at the other. Splitting pairs (e.g. swapping one orange with one blue but putting them right at the far end) will completely scramble the transmission as the go and return of each of the four circuits must form a twisted pair to have the correct characteristics.
Click to expand...
Yes, you are right they were not pushed in far enough. It seems to work fine now I have inserted them further in.

With regards your last paragraph I'm not sure what you mean as I believe I have the sequence correct? If you see post #6 you will see I have used T568A, however I realise T568B is usually used. Does it make a difference which one you use?
 
happyhippydad said:
Does it make a difference which one you use?
Click to expand...
No. As long as you use the same method at each end. Most modern equipment will auto-sense A or B sequence if it's relevant.
[automerge]1583704330[/automerge]
Oh... before I forget... don't bother making up patch cables if you need 'em. Just buy them in... it's cheaper, easier and looks better.
 
I believe I have the sequence correct
Click to expand...

Yes, my apologies, I thought at first that the brown/white and orange/white were interchanged but now I see it on a proper screen it is indeed correct 568A.
 
Here's a video for pass-thru with Klein tools crimper.
View: https://www.youtube.com/watch?v=9HDR6T_w4SU

I have only recently started doing this stuff, and never had a fail yet...
I have not very good eyesight, so actually I leave the tails extra long so I can thread each core into the connector individually, verify they are in the correct sequence then pull the excess through so the outer jacket is right into the connector, crimp and cut off the excess in one go. Those with good sight and nimble fingers can do this in seconds.
 
happyhippydad said:
View attachment 56235 View attachment 56236 View attachment 56237
Click to expand...
Them crimpers are naff buddy. They'll work for your first 50 odd crimps but then unreliable after that.

As mentioned before your better of using the feed through crimpers and the compatible crimps. Your spending a bit more but they NEVER fail.

I use these ones: Klein Tools Compact Ratchet Modular Crimper - https://www.NoLinkingToThis/p/klein-tools-compact-ratchet-modular-crimper/8309K?tc=BA8&ds_kid=92700022850516740&gclsrc=aw.ds&ds_rl=1241687&ds_rl=1245250&ds_rl=1244066&gclid=CjwKCAjwgbLzBRBsEiwAXVIygBRzgl-M0yvbnR4gXL18blnqfkaZrKExtZcFkaPUM2tic82WTsi1FhoCuGAQAvD_BwE
 
@happyhippydad if its any consolation I always find them fiddly to do whether cat 5 or 6. Wires are too small and my eyes are too old. Best advice I can give is to take your time and allow for lots of waste to be cut off. I also use the Klein crimp tool and the through type RJ45 connectors
 
There are uses for a "mirror opposite" cable in networking with RJ45 connectors. I'm not sure this is one of those situations, though.

Agreed on the tester.

(Removed link - SC)
 
Last edited by a moderator:
UNG said:
Can you explain?
Click to expand...

Back in the day, when switches and hubs weren't cheap, you could connect two PCs together using a crossover cable. If memory serves, you'd use the T568A standard on one end and T568B on the other so the cores in the connectors went something like this...


Code: 
orange/white -> green/white
orange       -> green
green/white  -> orange/white
blue         -> blue
blue/white   -> blue/white
green        -> orange
brown/white  -> brown/white
brown        -> brown

These days you'd need to factor in the blue/brown pairs as well I think as for higher speeds I think they form a data path and you'd need to be careful with POE devices
 
SparkyChick said:
Back in the day, when switches and hubs weren't cheap, you could connect two PCs together using a crossover cable. If memory serves, you'd use the T568A standard on one end and T568B on the other so the cores in the connectors went something like this...

Code: 
orange/white -> green/white
orange       -> green
green/white  -> orange/white
blue         -> blue
blue/white   -> blue/white
green        -> orange
brown/white  -> brown/white
brown        -> brown
Click to expand...
Crossover cables are still used today in some peer to peer applications although auto negotiation has somewhat reduced their use these days
SparkyChick said:
These days you'd need to factor in the blue/brown pairs as well I think as for higher speeds I think they form a data path and you'd need to be careful with POE devices
Click to expand...
This is the big minefield these days mixing POE and data does not normally end well
 
Zerax said:
Oh... before I forget... don't bother making up patch cables if you need 'em. Just buy them in... it's cheaper, easier and looks better.
Click to expand...
Some large patch frames I have worked on you had to make patch cables of the correct length and colour if you didn't want the head of I.T. to descend on you. On one site they had a patch cable trolley with all the different coloured cables and termination kit so you had no excuse
 

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