Richard A Downing wrote:
My bungalow has an old fashioned telephone system consisting of a BT
cable connected to a grey box (about 70x40mm tapered with a single
screw fixing). From here there is a wire to another identical-looking
box - only two core of the wire are connected). From this second box
there are two wires going to BT/RJ-11 sockets (65mm square surface
mounted bearing the old 'T' BT logo) - there are six wires connected in
at least one of these - there are three boxes and the interbox wiring
is not easy to trace in the loft. I have ADSL filters on all the used
sockets, of course.

Now I'm about to modernise everything, and it's a convenient time to
replace this wiring.

1) Can I install a modern Master Box directly from the first grey box?

Technically and practically yes, 'legally' no.

Or do I have to pay BT to do this? (I'm aware that there is moderate
voltage (-48V ?) on the wires!)

Legally yes, and yes there's about 50 volts DC across the line (changes
to 75V 18Hz when ringing ISTR)


2) Can I then wire new extensions from the master to ADSL-filtered
wall sockets throughout? I'll want 5-6 sockets, although I don't
foresee that many instruments - probably: Sky-box, ADSL modem,
Speaker-Phone and DECT-basestation (REN 4).

Pointers to FAQs/HowTos would be helpful. Thanks in advance.

After whoever installs the master socket, you can (legally) replace the
lower half of it with an ADSL master filter unit. There are two
versions of this, both with connections for onward internal network
(filtered) but also a version that provides an additional unfiltered
feed for an ADSL connection away from the master socket location.

Have a surf around in this site:-
http://www.clarity.it/acatalog/telecoms.html