Clive George, in article ,
says...


I discovered I had two master sockets set up in ours (one was
essentially bypassed, it was just sat on the circuit as an extension),
but it was enough to pull my connection speed down from 6Mbit to
3Mbit.

Would an ADSL faceplace help in that instance?

If the two master sockets are in wired correctly as a master
and a slave, then yes - but it's possible two faceplate
filters may be needed if they are simply wired in parallel on
the incoming BT wires.

I've seen this where a system, having two phone lines was
"converted" back to a single line. The customer probably
wanted both sockets live so someone simply connected the two
masters onto the one incoming line rather than correctly wire
one as a slave off the one master or replace one with a slave
socket. If you have this arrangement, then both masters are a
combined "point of demarcation" so you need two faceplate
filters - or pay for the regularisation of the circuit.

You can't mistake a modern master with its divided faceplate
and the visible screws that only remove the lower half. With
these, simply replace the lower faceplate with a filtered
version from e.g. ADSLnation, and reinstall the house wiring
onto the correct terminals on the back of the filter or use
the front telephone socket.

If it's an old installation, then the master and slave sockets
could be externally identical with both having the old BT or
even a GPO logo. You can only determine which is the master
by examining the internals for the extra ring circuit
components which includes a largish capacitor. If you have
these, then you cannot fit a faceplate filter unless the
master is also converted to the new type - which you aren't
supposed to do, unless...

--
JohnW.
Replace the obvious with co.uk in 2 places to mail me.