Phone Signal over Cat5e

[coder]

Hi all,

This is my first post on the Forum, and I'm someone will be able to assist. We moved into our house just before Christmas last year, and the previous owner had built it to his specification.

There is a full Cat5e network throughout (double RJ45 sockets in most rooms), but unfortunately only one telephone extension socket, which is located in the conservatory. Until now, we have been using a single phone in the conservatory, but now I want to add in another in my home office. Since I do not wish to install an extension into this room, I was thinking to use the existing Cat5e cable with the necessary jacks adapted to my needs.

The telephone that I wish to use came with an RJ11 > BT cable, in which only two wires were used. Here's what I have tried:

Remove BT jack from end of phone cable, and attach RJ45 with two cables attached to the middle two pins of RJ45. Then, on the patch panel, I have an RJ45 > BT cable. I have connected the same two wires (green + red) on the latter cable to the middle pins on the RJ45 jack once again. Unfortunately, the telephone I want to use does not receive a dialling tone.

I am sure that it must be possible to achieve this, so can anyone explain where I'm going wrong? Here's an outline of how the wiring looks right now:

Telephone > RJ11 connector > red + green wires > RJ45 (middle pins) > RJ45 middle pins > red + green wires > BT connector > master socket > drop cable.

Have I just connected the wrong wires to the BT connector? There were originally four in the extension cable that I used, so I assumed (perhaps wrongly) that I only needed the green + red.

I hope this makes sense, and I would certainly appreciate any additional information or advice.

Thank you,
Ben.

 

[mattylad]

You should be able to do this.

Try one of these http://www.maplin.co.uk/bt-to-rj45-adaptors-22940

Someone else may be along later with more info.

 

[cajar]

I think you are correct that the problem is with this part of the circuit because everything else sounds ok. Check for 50v up to your home office, then strip the wires and hold them against pair combinations of your telephone cable until you get dial tone.

 

[kjacko]

Sky use the white and white/blue conductors in their telephone cable.
A technician told me its the same in cat5e cos he'd done it.....not tried it myself though.

 

[rjm2k]

You should be able to do this.

Try one of these http://www.maplin.co.uk/bt-to-rj45-adaptors-22940

Someone else may be along later with more info.

I got a couple like that off ebay, only problem is I can't find a RJ45 to BT to allow me to plug a phone into the other end!

 

[kjacko]

modtap adaptor?

 

[Lectrician]

You should of cut the phone cable almost in half, and lugged an RJ45 onto each cut, both identically. That would be the simplest method for you. It doesn't matter which pairs you use then (for a flat cable, the best way is to use the middle 4 pairs, and the keeps the pairs as they should be too).

Secondary line mods would be the better choice, and then make yourself a pigtail from a BT style plug to an RJ45.

For the pigtail, you would need to follow this code:

Untitled

• Lectrician
• 3 Aug 2012
• 1

 

[plugwash]

It sounds like you have connected the wrong pins somewhere along the line. The actual phone signal on a BT plug is on the two pairs that straddle the middle, not on the center pins.

 

[SimonH2]

What I do when I need adapters both ways (ie BT plug to RJ45 and RJ45 to BT socket) is use a phone extension cable. Cut it in half - I usually cut it (say) 9-12" from the socket end as I usually only need a short adapter at the phone end and a longer cable at the other end. Then crimp two RJ45 plugs on the cut ends - making sure that the same colours go in the same pins on both plugs.

The easiest set of pins to use is the centre 4, though you end up with a "non-standard" setup that's incompatible with any "shop bought" adapters (such as the ones someone posted a link to). As far as keeping pairs intact, it's OK as the signal (pins 2 & 5 on the BT plug) will end up on the 3 & 6 pair on the RJ45 (green pair on 258A/568B wiring which is the most common).

With a little practice, you should be able to get the wiring Lectrician shows a diagram for. If you study the diagram you will see that if you flip the cable the right way up then you'll avoid having to cross the wires for the 1&2 and 4&5 pins on the RJ45. Then you "just" need to push the centre two wires out to one side, push the outer two wires in together, and put enough set in them so they'll stay like that till you get them in the plug. Yes, it is tricky, but if you keep trying you'll find it is doable - just don't crimp the plug until you are certain you've got them in the right slots.

 

[coder]

Thanks for all of your comments and help. I was able to solve this by re-looking at the pin configuration on the original cable that came with the phone. I rather stupidly assumed that it used typical wiring, which it didn't.

Everything has been solve now - with the help of you all!

Thanks,
Ben.