telephone wires twisted pairs

[TNTasha]

Hi. Does anyone know whether it is important to twist the ends of telephone wires together when joining pairs to make a connection in the telephone jack socket? I've read that it's important to twist the ends of the two wires together a little bit and then insert into the connection block. But then I've read that if you're using an IDC tool to insert your wires that you need to leave the insulation on the wire and insert each one into the block one at a time using the IDC insertion tool. The tool pierces the insulation and creates a good contact join between the wire and the block.

Is this just two ways of doing the same thing? If so, are they the correct ways of doing it and is one way better than the other? It seems like using the IDC tool means that the wires will connect to the block but not "directly" connect to each other, while the original method of twisting them together connects them directly. This minor difference may be irrelevant, but sometimes there are weird physics.

Thanks in advance for any advice.

tasha

[VirtualT]

if you're using an IDC tool to insert your wires that you need to leave the insulation on the wire and insert each one into the block one at a time using the IDC insertion tool. The tool pierces the insulation and creates a good contact join between the wire and the block.

This

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[TNTasha]

Thank you VirtualT. The IDC tool approach seems good.

[VirtualT]

Thank you VirtualT. The IDC tool approach seems good.

It is trust me, I do it for a living

[Shalodge]

If you are using a "punch down" terminal block only place one wire with the insulation on in each 'slot'. If you wish to continue on to another block you will find that there are 'slots' that are simply bridges to allow you to continue the circuit.

Do not place 2 wires, twisted or untwisted, in a slot as the spring jaws in the slot will only hold the bottom most wire (they are like a "V"). This will be why many folk tell you to twist the wires. If you lay them one on top of the other into the slot only the bottom one will hold, but the correct approach is .. one slot, one wire. If you must connect multiple wires dont use a punch down phone jack..

[VirtualT]

If you are using a "punch down" terminal block only place one wire with the insulation on in each 'slot'. If you wish to continue on to another block you will find that there are 'slots' that are simply bridges to allow you to continue the circuit.

Do not place 2 wires, twisted or untwisted, in a slot as the spring jaws in the slot will only hold the bottom most wire (they are like a "V"). This will be why many folk tell you to twist the wires. If you lay them one on top of the other into the slot only the bottom one will hold, but the correct approach is .. one slot, one wire. If you must connect multiple wires dont use a punch down phone jack..

In a krone block type terminal, 2 wires per slot is perfectly fine as long as you are using the correct gauge of wire for the terminal

[Shalodge]

Ok .. It is possible to punch down two wires in a punch down block (Tele jack).. no denying that .. but it is not reliable and certainly not best practice where I come from..

Might be ok in a telephone wiring application (but not to me) but it will not be acceptable in data patch panels or jacks. I suspect it is the no 1 cause of ADSL issues these days where DIYers are installing telephone jacks here there and everywhere using scredrivers and knives!!

The biggest issue I am facing now is unreliable punch down blocks mangled by screwdrivers, multiple and incorrect sized conductors etc. It leads to the most diabolical faults..

http://en.wikipedia.org/wiki/Punch_down_block

[TNTasha]

Hi all. Thanks for the useful info about the two-wires-per-slot caveat. I have an old BT 3-wire telephone jack socket that has been relocated on the other side of the wall. There are two wires connected per slot, in slots 2, 3 & 5. They are stripped at the ends and twisted around each other and inserted into their respective slots. After relocating the jack I had difficulty reproducing the twisted wires connection... they kept slipping out. After some research I decided to get a krone IDC tool.

I need to connect two wires per slot. Can you suggest the best approach?

Thank you.

[Wayne]

In a krone block type terminal, 2 wires per slot is perfectly fine as long as you are using the correct gauge of wire for the terminal

krone are good but the phone jacks are not made quite so well. They are generally made with 2 punch terminals for each wire of the pair (2 wires, 4 terminals) to allow joining (daisy chain).

[Wayne]

After some research I decided to get a krone IDC tool.

I need to connect two wires per slot. Can you suggest the best approach?

Thank you.

Try putting one wire on top of the next and see if the top one pulls out easily. The problem could be that the IDC grabs the insulation and the wire appears hard and fast when it isn't a good electrical joint. If you have a proper krone tool it will nicely cut off the end of the wire for you - if you use the cheap plastic tool that some come with you could make the wires a little longer, push them on the connector and solder the end a little for the electrical join.

[TNTasha]

Thanks everyone for the advice and the cautions. I have a proper IDC tool that cuts the wire off at the end. I have an old BT telephone jack with 6 terminals, with # 2 and #5 seemingly the important telephone terminals and #3 being the phone ring. Currently there are 2 wires per terminal in slots #2, 5, 3 (& the remaining 3 terminals are empty). I can see why this isn't the most stable as the second wire inserted is not quite as solidly connected. I'm not sure which of the other terminals would be the bridge terminals for slots 2 & 5. So, I either have to attempt to put 2 wires into each slot or figure out which are the bridge terminals in order to put 1 wire per slot.

[Wayne]

Thanks everyone for the advice and the cautions. I have a proper IDC tool that cuts the wire off at the end. I have an old BT telephone jack with 6 terminals, with # 2 and #5 seemingly the important telephone terminals and #3 being the phone ring. Currently there are 2 wires per terminal in slots #2, 5, 3 (& the remaining 3 terminals are empty). I can see why this isn't the most stable as the second wire inserted is not quite as solidly connected. I'm not sure which of the other terminals would be the bridge terminals for slots 2 & 5. So, I either have to attempt to put 2 wires into each slot or figure out which are the bridge terminals in order to put 1 wire per slot.

The old 'master/slave' type jacks don't have any spares - pin 1 of the connecter goes to terminal 1, 2 to 2 etc. They were made to better connect 2 wires per slot so long as both wires are the same size. There were a few issues (not always 100% reliable) which is one of the reasons for the new '2 wire' sockets having 2 groups of 3 terminals to enable bridging.

[Wayne]

I should add to make it clear - they were made to have 2 wires as a installation generally 'daisy chain' with the main line coming into the 'master' jack (the one with the capacitor) and then a sub circuit feeding off to the 'slave' socket for an extension phone. The main circuit is 2 wire from the street and the master socket splits out the 'bell' line (what the capacitor does) to feed 3 wire to the slaves (all daisy chained together).

In our internet/ADSL world it was found that the 3 wire bell system unbalanced the line and that ADSL works better if 2 wire (and let each phone pull out it's own bell) so many houses have been converted. You should only be able to buy the 2 wire sockets these days (or at least the 3 wire are hard to come by).

[TNTasha]

Thanks Wayne, I understand things better now. Thanks to everyone for being so helpful.