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Changing an Old Phone Wire for a New One

Postby Moolann » Sat Sep 23, 2017 7:03 pm

Hi all

Looking for some advice before changing the old phone line in my first house.

Recently redecorated and unpinned the old wife from the wall and removed the sockets. The wire is probably about 20+ years old and looks horrible so wanted to change it for a nice new one. As well as the brown box by the door.

There is a black wire that comes in from the outside, there is a small box where the blue and white wires connect to the internal old line I want to change.

I imagine that it is as simple as using a new wire to replace the old one, and buying a new connector/box to connect the black wire to the new indoor wire.

Is there any issue with this? Also is there likely to be any issue with not being able to disconnect the power to the black wire?

Thanks for the help,

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Simply Build It

Postby Mr White » Sun Sep 24, 2017 9:01 am

After the "black cable" (Drop wire) comes into your house and is terminated its now upto you what you do with it. So if you want to change it no worries.

It will be "live" all the time (at 50 volts) so I would suggest you connect your new cable to the phone sockets in your house first, then lastly connect it to the box where the black cable comes in.
The black cable is supposed to terminate in a "Master" BT socket. The idea being you can remove the bottom half of the front plate and connect your house phone wiring to it, then plug it back in.
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Postby ericmark » Sun Sep 24, 2017 4:06 pm

There are two wires used as it enters your house, then there is a master socket which turns it into three wires, the third wire works the bell, the polarity is swapped to make bell ring so if wrong way around then bell does not work, the master socket also has a spark gap to stop electrical storms damaging your phone. Sorry can't remember which way around the two wires go.

The phone socket only uses 3 of the 6 connections there are three types of plugs in general use, the old 1/4 inch jack plug, and the new RJ11 and similar and smaller RJ9 / RJ10 / RJ22 the latter normally found as part of the phone, the RJ11 is normally what is found on the phone socket, You can get filters for broad band where a RJ11 plug has a RJ11 socket for telephone and RJ10 for broad band.

Not a clue why but with RJ10 centre two contacts are used, and with RJ11 the 2 and 5 contacts are used and 3 for the bell. I found with a fax machine it swapped 2 and 5 which stopped the bell ringing.

However with cordless phones and computer modems the terminal 3 is not used and it does not matter if 2 and 5 swapped. It only matters with old hard wired phones.

The cable has twisted pairs, this twist helps stop interference so you need to use a pair and not one wire from one pair and another wire from other pair, also needs to be for telephone I used alarm wire as 4 pairs and wanted two sockets, found it picked up white noise.

The incoming socket should be open reach and from that socket it is all yours, but mothers house still has old brown box and an earth stake for the party line. Dad put phone lines everywhere and we really don't know where they run, but today only really need one socket with the cordless phone and router and may be one old one with bell for use in power cuts.
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