Tech Support > Computers & Technology > Internet & Broadband > ADSL Detection
ADSL Detection
Posted by do.not.waste.your.time.emailing.me@this.address.it.is.invalid on July 5th, 2005


I understood that when BT activate a pots line with ADSL it should
make no difference to the voice capabilities of connected phones.
This allows activation without ADSL modem and filter being available
at the time of activation.

I also understood that the filter, for phones, was necessary only if
there was an ADSL modem connected, live and synchronised / attempting
to sync with the exchange.

If my understanding is correct then what happens, and when, in the
exchange to the pots line when all my connected ADSL equipment is
powered off / disconnected.

The reason I ask is that I have some equipment which the manufacturer
insists can only dial, connect and download / upload to its server if
all the ADSL equipment, including filter, is removed.

This little device won't talk to its server as specified. It has been
replaced and the new unit doesn't talk, (the old and new connected
OK, but doesn't do its business, and listening to the line it sounds
like a low speed modem). When it fails there are no error messages.
the device only displays on hook, dialing and downloading!

I tried on my son's pots line (not ADSLed) and the unit connects and
does its business correctly. Monitoring the line, it didn't sound
much different either!

So I assume that the ADSL on my pots line is upsetting the connection,
even with the ADSL modem and filter removed.

So what happens to an ADSL activated pots line when there is no ADSL
modem connected?
And when does it happen, like immediately or after some time?
Should the line lose all the ADSL signals and then appear identical to
an unactivated pots line?
--
cerberus

Posted by Phil Thompson on July 5th, 2005


On Tue, 05 Jul 2005 10:28:11 +0100,
do.not.waste.your.time.emailing.me@t...s.it .is.invalid wrote:

I believe the DSLAM sits quietly waiting to hear from your modem, and
which point it sends ADSL frequencies down the line and tries to
train.

An enabled line will go through either a splitter or a line card at
the exchange end additional to the standard exchange connection.

Phil
--
Tiscali - dialup speeds at Broadband prices, see
http://bbs.adslguide.org.uk/postlist...&Board=tiscali

AOL - the unlimited ISP of choice for heavy downloaders.

Posted by Nigel Molesworth on July 5th, 2005


On Tue, 05 Jul 2005 10:28:11 +0100,
do.not.waste.your.time.emailing.me@t...s.it .is.invalid wrote:

Have you tried plugging it in via the TEL socket on a filter?


--
Nigel M

Posted by Peter Parry on July 5th, 2005


On Tue, 05 Jul 2005 10:28:11 +0100,
do.not.waste.your.time.emailing.me@t...s.it .is.invalid wrote:

Not quite - the exchange end termination changes and a bandpass
filter is used in the exchange to separate the telephone and DSL
signals.

It remains connected via the bandpass filter.

It would be helpful if you could describe this equipment more fully.
Most equipment for connection through the normal analogue telephone
line operates below 4kHz and should not be affected by DSL filters.
Some equipment such as Redcare uses out of band signalling but you
seem to be describing a normal modem.

It is possible the ADSL microfilter you are using and the equipment
are not compatible (some filters are better than others) but if it
won't work at all I'd look elsewhere first. Has this equipment ever
worked in the location you are now using it? Does it work if you
plug it directly into the test socket behind the NTE5 faceplate (if
you have one)?

Possibly, but by no means certainly. A fault in the premises
extension wiring can also produce the result you describe.

No, you retain the exchange filtering - but it should have no effect.

--
Peter Parry.
http://www.wpp.ltd.uk/

Posted by do.not.waste.your.time.emailing.me@this.address.it.is.invalid on July 5th, 2005


On Tue, 05 Jul 2005 14:07:53 +0100, Peter Parry <peter@wpp.ltd.uk>
wrote:


At the risk of off topic abuse, it is a Snooper S6-R.

No microfilter is used. The device is plugged into the NTE front
socket, with nothing else connected.

On the ADSL enabled line, no. On a different non enabled ADSL line in
the same location, yes, but that line is now disconnected. (Cancelled
after its initial 12 month contract was reached).

The arrangement of the extensions is that they can be completely
*unplugged* from the NTE front socket. (I use a 'patch panel' for
extensions (not really necessary now with only the one pots line). So
when the extensions are unplugged there is only the NTE front socket,
with *no wiring connected at all*, plugged into the test socket. The
device fails in the front socket with *all* this other equipment
disconnected. I suppose there may be a problem in the connections
from front socket to test socket but everything else, dialers, DECT,
dummy dialer, extension and ADSL modem / outer all function without
*apparent* error when connected / reconnected into the NTE front
socket..

It fails with *all* premises wiring and other equipment disconnected.

That is what I thought. That is why I stripped everything down the
basic incoming BT line, NTE and connection lead (which has been
metered out and replaced) to the device

Maybe I ought to try the Snooper plugged into the microfilter, with
and then without the ADSL modem connected, as Nigel Molesworth
suggested. If I can get the device to do its business with
everything else connected and working then I am not inclined to
investigate the root cause of the problem, but it intrigues me. I
will try it out and update with the results.

--
cerberus


Posted by Peter Parry on July 5th, 2005


On Tue, 05 Jul 2005 15:39:50 +0100,
do.not.waste.your.time.emailing.me@t...s.it .is.invalid wrote:

OK - so not a communications device as such. The chances are the
modem design is a bit of an afterthought and left as it was for other
markets.

Have you tried it in the socket behind the NTE5 front plate? (Remove
the lower section by unscrewing the faceplate screws). (I know you
said everything had been disconnected but .. :-) ).

Any such device must work in the low frequency end of the telecoms
spectrum and if correctly designed and built will work as any other
modem does and would not be affected by ADSL. I'd guess the modem
design, in common with many low cost Chinese electronic items, is
designed and manufactured for US line level settings which differ
from UK ones. Does it have the "crossed hockey sticks" mark?

Yes, would be interesting to hear the results. The UK distributor is
talking horsefeathers about correctly filtered ADSL affecting their
equipment if it is designed and manufactured to European standards.

--
Peter Parry.
http://www.wpp.ltd.uk/


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