Joining erthernet cables

[Squid]

No one mentioned Wago's?

 

[Midwest]

No one mentioned Wago's?

I did think that, but didn’t want to embarrass myself

 

[Midwest]

Just remember, when connecting the cable to any connection box, keep the cables twisted for as long as possible.

Why is that?

 

[Midwest]

CAT5 6 BT PHONE DATA CABLE REPAIR SPLICE JOINER 2 WIRE JELLY CRIMP CONNECTORS | eBay - https://www.ebay.co.uk/itm/CAT5-6-BT-PHONE-DATA-CABLE-REPAIR-SPLICE-JOINER-2-WIRE-JELLY-CRIMP-CONNECTORS/262906961146?hash=item3d3679dcfa:m:m0efo6Q_HMZU_sAC-Et4aWQ&frcectupt=true

Is that the ‘infamous jelly crimp’ ?

 

[davesparks]

Why is that?

The twisted pair is the cables major defence against external inyerfence.

The basic idea is that one conductor carries a negative image of the data on the other. So if logic 1 is +5V on one conductor it will be - 5V on the other.
As the pairs are twisted together they will both pick up near identical interfence.
The device which receives the data will invert the negative signal so that the data will be the same as the positive signal but the interference will be inverted.
Then by merging the signals the interference will cancel out and the original data should remain intact.

 

[davesparks]

Is that the ‘infamous jelly crimp’ ?

Yes, not much good for cat 5 if carrying high speed data.

 

[davesparks]

rj45 connector on the end of the existing cable and on the end of the new cable. rj45 coupler. thats the right way to do it.


RJ45 Cat6 Coupler - White - Data Comms Direct - https://www.dcdi.co.uk/shop/rj45-cat6-coupler-white

Right way according to who? Is this just your opinion or is there something else to support the statement?
That method looks quite shoddy and in my experience isn't the most reliable or easy to get right.

 

[Squid]

FFS just twist them together and use the minimum amount of tape to wrap the cable as you are a right git, it will unravel itself in the sun in a few months time though........ all this fussing around is putting us data cablers out of work, next electricians will be erecting scaffolding....... sheeeeeesh

I maybe having a giraffe.........

 

[Deleted member 105166]

I've used these, generally with good results:
Junction Box / Inline Coupler IDC for CAT5E / CAT6 - https://www.tlc-direct.co.uk/Products/CXSM315.html

Obviously, any joint is a weakness and if the option exists to pull a new cable that will always be better. If they are going to be inaccessible, test each line before concealing.

 

[brains-lans]

Right way according to who? Is this just your opinion or is there something else to support the statement?
That method looks quite shoddy and in my experience isn't the most reliable or easy to get right.

Hi Dave, Just my experience really. Its more of a right way to do it than using BT jellys or twisting the strands together and taping.

I see there are products that exist i wasn't aware of that do it well. But in a panel where there shouldn't be a lot of movement, the rj45 coupler isn't a bad device for the space it takes up (minimal) and they are designed for joining two ethernet cables together so are up to the task.

Ive been working in datacentres for over 20 years so the crimping part to me is the easy part, i appreciate making these off can be difficult if you don't do it regularly.

Still though - one cable of the right length would be best, but life is rarely perfect.

Brian

 

[Lucien Nunes]

Davesparks' clear and concise description about how twisted pairs reject interference works the other way too - it stops the pairs radiating interference into each other i.e crosstalking. There are lots of subtleties to minimising crosstalk such as different twist lengths so that one core of one pair never repeatedly lies alongside one core of another pair.

Then there's the issue of characteristic impedance, which is one of the things that has to be kept as accurate as possible at joints. When dealing with high frequency signals, cables are much more complex than just a series resistance and insulation resistance. One parameter is the characteristic impedance, which is what a cable looks like to a source driving a very short pulse into the cable. When you change the construction of a pair in any way by spreading the cores apart, or adding more insulation, or changing the conductor diameter, the impedance changes. At each impedance change, part of the signal is reflected back to the source. If there are serious mismatches of impedance multiple reflections can occur and the true signal can be attenuated to the point where the data is corrupted, even without external interference. Data plugs, jacks, patch panels etc are all designed to preserve the characteristic impedance as far as possible.

Jelly crimps make an excellent electrical connection which is why were so popular for voice lines. But their size, and the fact that pairs have to be parted to fit them, spoils the high-frequency characteristics of the pair as far as impedance, crosstalk, interference rejection etc. are concerned, therefore they are not really suitable for data lines.

A carefully constructed solder joint can work well but I do mean carefully. The twist layups of the pairs must be preserved, and the insulation thickness, and the position of each of the joints needs planning, it's not as simple as making sure the connections are electrically sound.

 

[Squid]

Makes note in Moleskin notepad not to invite Lucian to the house warming party.............. ;o))))

 

[decomplexity]

I have used several of the inline couplers recommended earlier by Tony Mitchell with no problems. Just use a decent punch-down tool (e.g. Krone) and for consistency use the same pin-outs (Type A or B) as used by the end points - almost certainly Type B.

 

[pirate]

This is a very interesting thread, so thanks to all you knowledgeable contributors for your input!
I recently had my introduction to making patch cables, so i could have a wall-mounted socket thingy with a patch cable from there to my modem/router thingy.
A pal said to get a pass-thru type of crimper, which i did, and that made the job much simpler when terminating the connectors...I could strip the cable way too long, which made it easier to get those 8 pesky wires in the right positions, then simply snug the cable up tight so the untwisted strands and the outer sheath slipped way up into the connector, and the crimper just cut off the excess. My eyesight is such that wearing a dentists loupe was extremely useful...wouldn't want to do it every day, to be honest.

 

[Squid]

This is a very interesting thread, so thanks to all you knowledgeable contributors for your input!
I recently had my introduction to making patch cables, so i could have a wall-mounted socket thingy with a patch cable from there to my modem/router thingy.
A pal said to get a pass-thru type of crimper, which i did, and that made the job much simpler when terminating the connectors...I could strip the cable way too long, which made it easier to get those 8 pesky wires in the right positions, then simply snug the cable up tight so the untwisted strands and the outer sheath slipped way up into the connector, and the crimper just cut off the excess. My eyesight is such that wearing a dentists loupe was extremely useful...wouldn't want to do it every day, to be honest.

They are called East Connects,

feel sorry for your wife if you have trouble fiddling with small things....... and holes.

 

[Squid]

I have used several of the inline couplers recommended earlier by Tony Mitchell with no problems. Just use a decent punch-down tool (e.g. Krone) and for consistency use the same pin-outs (Type A or B) as used by the end points - almost certainly Type B.

Most Krone tools are for phone cables, network cables are a tad thicker and harder to punch down and to cut, I use a Fluke D914.

 

[decomplexity]

Yes - the Fluke D914 is a lovely bit of kit if a bit pricey; ide al if doing lots of terminations.

 

[Squid]

Always buy the best that you can afford.

 

[Midwest]

I've had the old panel off. It has a pair of network cables to it, with each connection doubled up with wires, e.g. from one cable - brown and white brown wires and the other cable - brown and white brown wires into one connection. Why would they do that?

I know it’s starting to turn into a step by step guide

 

[rsgaz]

So, it doesn't use ethernet at all, just the cable. It'll be some sort of DC bus system then. Doubled up conductors because Cat5e is only 0.2mm² per wire.

Is there isn't another switch nearby, if both the network cables come from exactly the same place, then indeed it makes no sense. Daisy chained to another switch plate would make sense though.

Edit: Is the cable shielded at all or just UTP?