BT master socket change

[DIYspanner]

My uncle, who has broadband, has a BT master socket the same as at the top of this page


http://www.wppltd.demon.co.uk/WPP/Wiring/UK_telephone/uk_telephone.html


At present it has incoming cable plus an extension cable.

Is it feasible to change this master socket to a BT NTE5 master socket, obviously attaching the extension cable to the removable plate?

It is a 3 wire installation so a bell filter plate would help.

 

[plugwash]

Technically it's perfectly feasible.

Strictly speaking the master socket is owned by BT so you aren't meant to mess with it, in practice I don't think they really care too much unless you break something and try to get them to fix it.

Personally rather than messing about with bell wire filters i'd just disconnect the bell wire.

 

[kbdiy]

Yes, in a word, it is.

 

[DIYspanner]

Thanks for the replies folks.

As I understand, phones with 2 wire cords have their own bell circuit so the bell wire, no 3, isn't required.

So if the bell wire isn't connected, no need for a bell filter plate so the present master may as well stay put or does the newer BT NTE5 give increased broadband speed?

 

[bernardgreen]

or does the newer BT NTE5 give increased broadband speed?

The NTE5 with a filter front plate separates ADSL signals from the voice telephone wiring. This can increase broadband speed as it prevents the voice telephones and wring from affecting the ADSL signal.

To get the best speed you need to ensure there are no stubs on the wiring carrying the ADSL signal. ( A stub is a cable that branches off from the main cable, the equivalent to a dead end side street from a main road ) Some of the ADSL signal will go down the stub, be reflected at the dead end and return to the main highway after a delay ( the time to travel along the stub ). The modem see the signal followed by an echo ( from the stub ) and this degrades the ADSL signal as seen by the modem / router.

Hence you get the best results by separating ADSL from voice phone signals at the NTE 5. Then you have as many stubs on the voice phone wiring as you like as they cannot affect the ADSL signal.

 

[DIYspanner]

ref: Stub

Is an extension cable wired from the master, with no phone plugged into the extension socket, classed as a stub?

 

[bernardgreen]

ref: Stub

Is an extension cable wired from the master, with no phone plugged into the extension socket, classed as a stub?

Yes.

 

[DIYspanner]

Very informative feedback folks, much appreciated.

Just out of curiosity, on my own phone system, I have a extension that's not connected at the extension plate, just loose in the back box. This I suppose is stub.

Could this occasionally stop the phone ringing on incoming calls?

 

[bernardgreen]

Stubs will not affect the operation of voice phone systems. Loose wires may intermittantly short out the ringing current.

If the fault is that the bell does not ring on an incoming call but when you pick the phone up the caller is there then lack of ringing is possibly a ring trip. The exchange thinks the phone has been picked up to answer the call and therefore it cuts off the ringing voltage. Too many phones and /or micro-filters can cause ring trips. If it is a ring trip then the caller will hear a short bit of ring tone and then silence until you pick up the phone

 

[plugwash]

The NTE5 with a filter front plate separates ADSL signals from the voice telephone wiring. This can increase broadband speed as it prevents the voice telephones and wring from affecting the ADSL signal.

It's important to bear in mind the distinction between a "filtered front plate" and a "front plate with a bell wire filter".

The original NTE5 was designed pre-broadband and had no filtering at all.

When ADSL first came in BT introduced a filter plate which replaced the front part of the NTE5 and completely split the phone signal from the broadband signal. Various third parties have also made such plates.

However BT thought this was too complex for normal people to install. So they introduced the idea of leaving the phone wiring as it was and putting seperate "microfilters" on every phone. This was technically inferior but it worked ok in most cases with the speeds of the time (this was before the days of "max" products)

Some time later they introduced a filter on the bell wire to the new versions of the standard NTE5. Filtering the bell wire helps but it's still not as good as having full centralised filtering,

 

[DIYspanner]

According to this page

http://www.wppltd.demon.co.uk/WPP/Wiring/UK_telephone/uk_telephone.html

for the newer NTE5 master, the two incoming wires can be either way round to terminals A & B

Is this correct?

 

[Europlex]

for the newer NTE5 master, the two incoming wires can be either way round to terminals A & B

Is this correct?

Yes, even for the older ones

 

[bernardgreen]

[quote="DIYspanner";p="2938901"the two incoming wires can be either way round to terminals A & B Is this correct?

Yes, even for the older ones[/quote]
Correct for 99% of domestic installations. There are some situations where polarity is critical. Some answering machines and fax machines are polarity sensitive. Also some specialist modems / routers

In the old days of party lines reversing the A B meant calls were charged to the other party's bill.

 

[kbdiy]

In the old days of party lines reversing the A B meant calls were charged to the other party's bill.

Ah the good old days of Shared Service - polarity reversals and dry earth spikes! Happy days

 

[DIYspanner]

My uncle's phone/broadband which I'm looking at, has had the master socket in situ for 30 years or so, well before ADSL broadband.

Presently he has a phone plugged into the master with two additional phones plugged into extensions, the ADSL connected to one of these extensions.

All three sockets have micro-filters on.


I'll let him know about the newer NTE5 master.