bt telephone

snowman707

apologizes if this is the incorrect forum,

will a bt 120 corded phone work if I use a bt to rj11 adaptor, bought a bt phone from maplins and it will not work with my old lead which i know is pefrect the phone was supplied with a bt male and rj11 lead .. bt male being the house socket end.

maplins sell adaptors but the guy at the check admitted he hadnt a clue.

Thanks in advance

Solair

RJ11 and BT connectors are both "Crimp on" i.e. they're just slipped over the top of a piece of flat 6-wire phone cable and crimped onto the wires with a special tool.

They're both very similar 6-terminal connectors. In fact, the BT connector is quite obviously just a rip-off of RJ11 modified to make it incompatible with the older US standard to prevent people from plugging in 'foreign' phones in the UK back in BT/GPO's more paranoid days.

The phone line is however carried on different pins on the BT connector to the standard way RJ11 connectors are wired...

To avoid having to cross the wires over in the plug, some manufactures (particularly BT itself) just incorrectly wires the RJ11 connector, as if it were a BT connector and the terminals in the phone are wired to the wrong contacts (matching the cable).

The result is that a standard RJ11 cable, as used by eircom or any North American phone, will not work.

The phone should work fine if you use a BT to RJ11 adaptor.

The only other complication is that BT sockets split off the ringing signal and send it to the phone on a 3rd wire. While normal Irish phones (and most other phones in the world) use 2-wires only.

For this reason, make sure that the adaptor has a ring capacitor inside. Basically the adaptor should look a little bulky, sort of like the filters/splitters that you use with a DSL modem.

Although, with modern phones they should work with just 2-wire ringing.

Caller ID usually works, as the type of caller ID used in Ireland is one of the major EU standards and is used by some British operators e.g. Virgin Media but not by BT. Eircom's caller ID is identical to French or German caller ID and very similar to North American standards too.

Most phones can accept multiple standards.

snowman707

many thanks Solair,

very detailed and informative answer, I know where I am coming from now and will be able to get it up and running one way or the other,

thanks again

Solair

No problem!

There is surprisingly little info about the Irish phone system and how to wire extensions etc. They seem to just assume that people will figure it out themselves.

It's not a particularly complicated system and it's very DIY friendly i.e. it's just 2-wire and polarity doesn't actually matter (you can connect either way).

I just find a lot of the info that comes up online about it is actually applicable to the UK.

Telephone lines are surprisingly not very different world-wide. You just get some minor quirks in terms of how the internal extensions are done in some countries, particularly the UK.

You just need to get something like ... most hardware shops and the likes of Atlantic / Woodies and possibly B&Q should have them available.