I'll try to make this as concise as I can, but it may ramble a bit. Please
be patient 'cos I really would be grateful for help ...

Friend has existing BT analogue telephone line (let's call it Line A)
He also has, allegedly, a company-provided "ISDN line on a different
telephone number"
He's just changed employers and the "ISDN line" will be removed shortly, he
says
He's also just signed up to have broadband on his Line A
I went to his house yesterday to see if we could make use of the "ISDN line
wiring" (instead of laying out additional wiring) to get his Line A extended
to his upstairs office

That's when I started to get confused ...

There is only one BT cable coming into the house from the BT junction box
outside
The "ISDN line" seems to be on the extension wiring off that same line.
That is, originally (pre-ISDN installation), the BT line (Line A) had
extension wiring connected to provide an additional telephone point
upstairs. In the upstairs office, this wiring has been cut before it
reaches the outlet box and instead now connects into some sort of powered
box (with a pulsating green light on the front !!) which then feeds a
modem-type box with sockets to connect to his laptop computer and a
telephone.

So, despite having a "different telephone number" is the ISDN service
presented on the same physical copper wires as the Line A service? (how can
that work then?) and will the BT exchange (or BT technicians, or both!) get
horribly confused if they try to set up his broadband service on his Line A
telephone number if his past employer forgets to cease the ISDN service
(which on past evidence they might well do!) on the same line ??

Oh, there's a further confusion in that the incoming line seems to be
connected directly to the removable front plate of the master socket -
plugging the telephone into the 'internal socket' that's revealed when the
front plate is removed leaves us with a completely 'dead' phone. I thought
that couldn't possibly be correct, but then wondered if it was something
caused by having the "second line for ISDN" on the same wires ... (oh, and
finally, the Line A telephone that connects to the master socket doesn't
have any kind of filter but still works fine without any hissing or
whistling from a high frequency signal)

Grateful for any help.

From "Confused" of Hatfield, Herts.

On 20-Oct-2007, "Mike Faithfull" <mouse_potato@surfmail.com> wrote:

Are you sure that only two wires are coming in?
Off a pole can have two or more pairs.

On Sat, 20 Oct 2007 14:01:29 UTC, "Mike Faithfull"
<mouse_potato@surfmail.com> wrote:

It's probably a cable with two separate pairs in it. One for ISDN, one
for the POTS (Line A) line. That's exactly what I have here.

No.

Does sound a bit of a hack job, though. When you say ISDN, is this true
ISDN2e, or a Home/Business Highway job? What does it say on the front of
the box with the green light, and how big is it?

--
[ 7'ism - a condition by which the sufferer experiences an inability
to give concise answers, express reasoned argument or opinion.
Usually accompanied by silly noises and gestures - incurable, early
euthanasia recommended. ]

In an earlier contribution to this discussion,
Mike Faithfull <mouse_potato@surfmail.com> wrote:

The "single" wire coming in has almost certainly got 2 or even 3 pairs of
conductors in it - and can thus support two or more independent circuits -
one for Line A and one for ISDN, etc. What appears to be an extension is
probably where it splits into two circuits.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

"Bob Eager" <rde42@spamcop.net> wrote in message
news:176uZD2KcidF-pn2-FSfnb4hHwU2g@rikki.tavi.co.uk...
BT Home Highway was discontinued about a year ago.

BT Business Highway will be discontinued March 2008, see:
http://www.magsys.co.uk/telecom/tcomhist.htm

Both these are implemented with a (white) rectangular box about 6 inches
wide by 8 inches deep by 1 inch thick - see:
http://www.quaketweaks.com/bthomehighway.html nearly at the bottom of the
page. There may be different writing on the box to distinguish between
Business/Home versions.

ISDN2e still exists. It looks like: http://aaisp.net.uk/aa/isdnintro.html -
about half-way down the page. With ISDN2e you only get a digital
connection. If you want to connect an analog phone you need some extra
equipment. Typically this would be a router with a POTS output. Whatever
it is, it will not generally be supplied by BT.

It is unlikely that the cable coming to the property has only two wires in
it - almost certainly it has at least 4 - i.e. 2 pairs. Separate from the
HH/BH/ISDN2e box there will be at least one conventional master socket.
Wiring from this socket will run to the HH/BH/ISDN2e box and there may be
other wiring to the master socket for the "Line A" service. Careful
investigation of the incoming cable and any anonymous junction boxes would
be worthwhile.

It would also be worthwhile asking the decommisioning technician to explain
the wiring before any is disconnected, to allow discussion of how best to
re-use it. So it would be worth your while being present while the BT
technician does the work.

-- Graham

On Sat, 20 Oct 2007 18:05:58 UTC, "Graham" <graham@nospam.zen.co.uk>
wrote:

Indeed. But it might be Business Highway.

Indeed. I didn't want to complicate the issue. More likely to be an
NTE8...proper ISDN2e, which is what I have.

--
[ 7'ism - a condition by which the sufferer experiences an inability
to give concise answers, express reasoned argument or opinion.
Usually accompanied by silly noises and gestures - incurable, early
euthanasia recommended. ]

I think you actually have is just an ISDN line, nothing else.

Typically Basic Rate ISDN is used to provide:
1) a dedicated 128kbs data line, no POTS
2) 1X64kbps data + 1POTS
3) 2 separate POTS, no data

So the incoming line (which will just be dead if you connect a POTS a phone
to it)
goes upstairs to the ISDN NTE, the box with the line-powered light.
A pair of wires from one of the POTS terminals in the NTE goes to
the phone socket, and also back downstairs to the other POTS
socket, but this is a different pair to the incomming ISDN, but
it may well be in the same cable.

Different DDI/ MSN numbering is quite normal.

--
Graham

%Profound_observation%

"Graham." <me@privacy.com> wrote in message
news:ffdmiv$v68$1@registered.motzarella.org...
Lots of interesting information received, thanks everybody! I'll try to
answer the questions, if I can, but first, let me assure Graham that there
was a POTS service in existence before the ISDN came along, and it still
exists with the same telephone number as it always had, and the 'phone is
still plugged into the same master socket that it always was. I can quite
believe that there are two pairs coming in to the master socket, but if
that's the case, I still don't understand how they are connected.

The NTE (whatever that means) is about 6 inches square, and about an inch or
so thick, and AFAICR there's no obvious legend on the front, only this green
light that 'pulsates' rather than flashes, if you see what I mean - it sort
of "fades up" and then "fades down" without ever turning off, at about one
cycle per second. I would guess that it's a "proper" ISDN not a Home
Highway as it was provided by one of the high street Banks. I only got
blank pages from http://aaisp.net.uk/aa/isdnintro.html but none of the
pictures on the http://www.quaketweaks.com/bthomehighway.html page looks
like anything I've seen before.

Graham said "It would also be worthwhile asking the decommissioning
technician to explain
the wiring before any is disconnected, to allow discussion of how best to
re-use it. So it would be worth your while being present while the BT
technician does the work" I had kind of expected that the supplier -
whether by that I mean BT or the Bank, or both - would judge that it would
be more costly to de-install the equipment than it would be to just abandon
it (as the Bank has with the desk, chair, and HP printer/scanner/fax jobbie
they provided - the only thing they wanted returned was his laptop computer)
and disconnect the line at the exchange. If it IS 'decomissioned' the only
person likely to be present is his elderly Mum, and she can barely speak
English so getting any useful information from the Tech is pretty unlikely!

I rather suspect this is all academic, and eventually I shall end up
disconnecting everything from the master socket, identifying the POTS line
from the jumble of wires therein and re-connecting it in the "normal
configuration". Don't tell BT !!

"Mike Faithfull" <mouse_potato@surfmail.com> wrote in message
news:L56dncCkZIVJ9YfanZ2dneKdnZydnZ2d@pipex.net...
You may be correct, but it is also possible that the POTS line
was converted to ISDN with the configuration that I have
suggested and the original number retained for the POTS
phone. This will also explain why the original master socket
has no dialtone, the engineer left it in place instead of
replacing it with a junction box.

The thing that makes me think I may be wrong, and there
is indeed a separate POTS line, is you saying that you
have successfully got ADSL provisioned on it. Is that
signed and sealed?
--
Graham

%Profound_observation%

"Graham." <me@privacy.com> wrote in message
news:ffdrd1$l79$1@registered.motzarella.org...
Signed, sealed, but not yet delivered - i.e. an acknowledgement letter
confirming payment details, account name / password etc. has been received,
but he's waiting confirmation of BT putting the broadband signal on the line
....