Why does my telephone seem to need four wires?

[snowhead]

Have you just moved to this house?
Has the phone ever worked?

If you plug a phone directly into the Master you should get dial tone AND noise if you have Broadband, if you plug a filter in the Master then a phone in the filter the noise will go .

If not, unplug the master faceplate, all the internal wring should be connected to the faceplate NOT to the Master connections, that should just have B.t's 2 wires on it.
Plug the phone directly into the socket Inside the Master socket.

If you don't get dial tone directly in the Master you have a fault on the line, or your phone service is not enabled.

 

[Guitarist]

Great how people just ignore the time you spend replying...

 

[ralphonz]

Have you just moved to this house?
Has the phone ever worked?

If you plug a phone directly into the Master you should get dial tone AND noise if you have Broadband, if you plug a filter in the Master then a phone in the filter the noise will go .

If not, unplug the master faceplate, all the internal wring should be connected to the faceplate NOT to the Master connections, that should just have B.t's 2 wires on it.
Plug the phone directly into the socket Inside the Master socket.

If you don't get dial tone directly in the Master you have a fault on the line, or your phone service is not enabled.

Hi,

Thanks for the reply, i've been away for a week.

1. Yes, i have two phones. Both work but ONLY with a 4-core cable and NOT with a 2-core cable.
2. Yes, i've just moved in to this house. There is only one (master) phone socket.
3. I've got sky broadband, it works fine with the supplied filter. Both phones i've tested work with or without the filter but only when using a 4-core cable.
4. I've checked the internal wiring of the master socket. Only the orange and white cables are connected to 2 and 5.


The big question is why do the phones only work with a 4 core cable when everyone keeps telling me they only need two connectors? I have a bag full of BT - RJ11 cables and have tested with all of them. Only cables with four connections will give me a dial tone.

 

[Lucien Nunes]

I suspect the problem with the 2-core cables is not that they have 2 cores, it's which pins of the RJ11 they connect to. The BT431A plug has the line on pins 2 (B leg) & 5 (A leg), whereas the US convention for phones using RJ11 line jacks was to have the line on pins 3 & 4. Many 2-core cables will be wired 'crossover' to suit such devices, especially modems and fax machines.

If your phone RJ is wired for a 6P4C plug in the UK configuration it probably has its line on 2 & 5. Therefore a crossover cable will not work but a straight-wired one will; your 4-core cables are probably straight-wired.

Have a look at the core colours if you can see them through the slots in the BT plug or bleep them with a meter. You can usually see at a glance which pins are connected at the RJ11.

Lucien

 

[ralphonz]

Lucien Nunes,

Thank you for that information! It seems to have cleared things up for me.

I have 13 BT-RJ11 cables and all are wired to pins 3 & 4 on the rj11! Even the BT-RJ11 cable I recently bought from ebay UK as a "BT phone extension cable" is wired from 2 & 5 to 3 & 4. I guess this makes all the cables I have useless for UK telephones.

Thank you very much for your explanation.

 

[Lucien Nunes]

I don't know which pinout is more common in the UK now, most of the time I'm looking at things like audio conferencing units where 3-4 is normal, rather than telephones. If the job needs anything other than RJ45 to RJ11 I end up making it on the spot.

 

[ackbarthestar]

Ditto, Just cut off the old RJ11 and recrimp....