Telephone Experts Please - Part 2

Hi all
OK so I went round to mother's last night armed with my own cordless phone (Siemens).
The findings seemed inconsistent and were as follows:
Plugging our phone in showed similar levels of crackle-hiss noise as mother's. Unplugging the upstairs phone and filter seemed to massively reduce the noise. There was still some noise present when plugged direct into the master box rear connection (with filter included). I tried turning off fridge/freezer and heating to check that this was not the issue.
One very strange anomaly noted....
With everything plugged in: twin cordless phone and wireless modem into front connection of masterbox via splitter downstairs - and - corded phone via filter upstairs: When a call is made from the upstairs corded phone, the modem dropped its connection - then reconnected when the call was terminated.
Does this indicate a dodgy splitter? At first I thought maybe I was just unlucky and had 2 dodgy splitters. But then ISTR that they tried a cordless phone before they had broadband and gave up because of the interference.
Thanks to all
Phil
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Have you got the sort of master socket where removing the faceplate disconnects the internal house wiring and leaves a single socket behind it connected to the line? If not, would be worth fitting one. Then plug an ordinary cabled phone into the line, dial one digit to get rid of the dial tone and listen to the line noise.
--
*He who dies with the most toys is, nonetheless, dead.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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"Dave Plowman (News)" wrote

Thanks Dave
Yes the master has a removable faceplate. I tried this and plugged direct into the internal master socket and there was still discernible, though less I think, noise.
The one thing I may have missed though (talking to colleagues).... I was plugging the phone into the master socket with a filter attached. According to colleagues, the filter is not necessary if all other equipment (ADSL stuff in particular) is disconnected - is this correct? Therefore the problem may have still been with the filter.
Phil
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On 19/07/2011 09:11, TheScullster wrote

Yes. The filter prevents the higher frequency ADSL signals from reaching the phones, these signals are only present when you've established an ADSL connection so there's no need for any filters if you don't have an ADSL router or modem connected.

That could be a possibility.
--
Mike Clarke

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On mine, the filter is in the faceplate part. Remove that reveals a socket corrected direct to the line. It also disconnects the internal house wiring. If you have a noisy line then, it wants sorting.
--
*Never miss a good chance to shut up.*

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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On Tue, 19 Jul 2011 08:08:35 +0100, "TheScullster"

(In answer to you later post) I believe the ADSL side / link is only established over the line when the kit at the remote end (your ADSL modem / router) initiates it (to the DSLAM or whatever it is). So, yes, you wouldn't need the filter if the ADSL service wasn't on or if you weren't bothered about it being knocked out when you used the line.
Cheers, T i m
p.s. A mate has a BT / ADSL line and I've noticed quite a bit of 'line noise / mush' when I've used his phone. We have cable so not really that familiar with such things. ;-)
p.p.s. I was at a local shop a while back when I overheard one assistant asking the other 'if they had finished on the Internet as they wanted to use the credit card machine and that would cut the broadband off ...'.
When the customer was gone I suggested that wasn't 'right' and they replied that that was how the people who put the card machine in said it sometimes worked? I offered to check it out for them and as they knew of me (I was friends with the shop next door) they did. It turned out (as I suspected it might) that the filters / splitters were all in the wrong places and a few re-plugs got the card machine working without knocking the bb out. ;-)
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On 19/07/2011 09:27, T i m wrote:

Had a similar experience with a customer once. I was remote controlling a machine. and told them I would ring you back when it is fixed. Then every time they hung up, I lost remote control and had to ring them back again to re-enable it. I suggested they had their filter in the wrong place, which they were sure they did not!
Only finally fixed it next time I was on site and took apart the mess of extension leads, four to one adaptors, and rearranged the sequence so that both the phones were on the filtered side rather than just one.
--
Cheers,

John.

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On Wed, 20 Jul 2011 00:31:58 +0100, John Rumm
<snip familiar story>

<sigh>
I wonder /how/ these things get that way though? Whenever I confront something like that (and have done many-a-time when I was a Field Support Tech and when helping friends and family etc) I like to 'understand' how it's all connected together first / currently. So to do that I might first unplug one thing at a time, clear the lead back to where I can see it all then plug it back in and move on. Once I have a picture of how it is now I would then be able to clearly see if there were any technical issues with how it was and make adjustments accordingly. I've seen people randomly unplugging and re plugging stuff when there is no way they could actually know what went to what, even if they understood what was supposed to be where.
Like the 'can't get on the Internet problem I resolved (in about 10 mins) for a neighbour recently when the cable modem and router PSUs had been transposed (amongst other things) and causing all sorts of weird effects. I did exactly the same thing there ... traced everything back to where it came from and just plugged it all in correctly. The irony was then it 'just worked'.
Maybe a bit I take for granted in all this is that I do have an understanding of how stuff fits together and they simply don't. I just can't see how they don't! (Well, I do of course because there are things I'm not interested in or good at but they are normally things where you might not be able to use a bit of common sense / lateral thinking). ;-)
Cheers, T i m
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On 20/07/2011 09:59, T i m wrote:

The answer seems to be, they fiddle with things until the fit mechanically. They understand that the parts may be required, but not the subtlety that the order of assembly matters, as does ensuring a similar looking part that came with another bit of kit may not be a direct substitution, even if it does "fit".

The number of times I hear the intro of "I unplugged everything and put it all back together again" is amazing. Had one chap with intermittent broadband, who insisted in pulling apart his internal network and re plugging every time, because it "fixed it". I pointed out that all he was doing was the tech equivalence of a rain dance, and the only functional action that had any effect was restarting the router forcing it to remake a connection. More to the point he was likely to introduce unreliability by causing wear to all the sockets etc. (eventually got him to report a line fault, and BT fixed it).

It is probably yet another a case of "unskilled and unaware" (or the unknown unknowns if you prefer). One can comprehend some aspects of a job, like the fact the connector on the PSU should fit the socket. They may even understand the need for the voltage to match the requirements, however could still be ignorant of the supply current needing to be adequate, or the fact the polarity of the wiring of the connector might matter.
(I think I may have told the story before of gentleman who wanted to make use of a hand scanner (we are talking early 90's here) from the office machine on the secretaries desk, with his laptop. Having unplugged the scanner from the desktop (leaving its dedicated ISA interface card in her PC obviously), he was now confronted with a connector that did not fit any of the sockets on his laptop. So he chopped it off and re-terminated the lead onto a new connector! Eventually returned it the the secretary saying "this does not work", can you send it back? IIRC she phoned Logitech and told them the story. They were so amused, they sent her a free replacement!)
--
Cheers,

John.

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On Jul 20, 8:06pm, John Rumm wrote:

I heard of someone who used a similar 'technique' for upgrading their 486 to a Pentium.
Owain
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On Wed, 20 Jul 2011 20:06:54 +0100, John Rumm

I've fished a few USB plugs out of Ethernet ports. ;-(

Yup, True.

Most probably, yes.

;-)
Talking of that. Stepdaughter has had some dropouts on her TalkTalk ADSL broadband service and that is seen simultaneously by other people using the net there at the same time. The problem is getting her to contact Tech Support because she's frightened about being talked into doing something she wouldn't have done had she known the bigger picture (like when they have go people to do a factory OS restore and lost them all their data). Dad thought he had lost all his mails after talking to a Tech Support line but I just went round there and deleted the 'test' account they had got him to make. ;-)

Quite.
<snip>

NO!
I've seen so stuff but I've don't think I've seen anything quite as bad as that.

Nice.
Cheers, T i m
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On Tue, 19 Jul 2011 08:08:35 +0100, "TheScullster"

Life would be simpler if you tried just a plain simple corded phone.

It is quite consistent with what you have experienced which is probably ADSL noise.

Or you have faulty wiring or a faulty modem/router. From what you describe you do not have interference from any external source but are hearing a high level of noise produced by the ADSL signal.
If the upstairs phone is both noisy and dropping the ADSL data then it isn't being filtered. This may be due to a faulty filter or faulty wiring. The fault may be in the filter design so if possible when testing use another brand (some cheap ADSL filters connect the pin 3 ringing signal directly through instead of using only pin 2and 5 and a separate ringing capacitor in the filter).
The ADSL filter is really a "not ADSL" filter - it filters the ADSL signal from the line to stop phones both affecting the data stream and preventing the ADSL signal producing audible noise on the phone.
As the exchange equipment will continue to send data for some time after the modem is disconnected the first check is to take a nice simple wired phone and plug it in to the test socket so that and nothing else in the house is all that is connected. If you still hear noise leave it plugged in for half an hour and check again, it will probably be quiet.
Leave the ADSL modem OFF and put the face plate back to re-instate the internal wiring. The phones should be quiet.
Switch the modem back on and within a short time the noise should return.
If this is the case use an ADSL filter in the test socket (so everything else in the house is disconnected) plug in one plain ordinary wired phone connected via an ADSL filter and the ADSL router.
If there is still noise swap the ADSL router/modem for another - I have come across two Netgear routers which, when hot, generated large amounts of ADSL noise in the audio band where an ADSL filter has no effect.
If, with two routers and a plain wired phone and using only the test socket you still have a problem it is likely to be a dry joint on the external wiring - these can act as diodes and allow the ADSL signal onto the audio part of the system.
If that works OK you need to work your way through the house wiring. Start by unplugging everything from telephone sockets in the house and plugging your test phone and modem into the NTE5 faceplate. If there is no noise re-instate everything one item at a time making sure each device has an ADSL filter.

If it was an analogue phone that is completely irrelevant.
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"Peter Parry" wrote

Peter
Thanks for detailed diagnostic.
If the router is not "in use" (i. e. there are no PCs communicating/surfing) is it still generating some form of ADSL signal that will create noise?
Phil
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I once had crackling noise, very variable, which was traced by a BT engineer's standing wave gizmo to the overhead twin cable from my eves to a communal telegraph pole across the street. The copper wire was found to be corroded through in 6 places. This was before ADSL so only 40 kbps, but it was a bit intermittant on the modem.
Is this anything like your external connection.
rusty
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To clarify, different phones will draw a different static current (AIUI) and affect the conductivity of moist copper verdigris in a broken cable. So the cordless phone is probably a different loading to the original phone and could show different fault conditions.
rusty
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On Tue, 19 Jul 2011 10:23:37 +0100, "TheScullster"

Yes, the radio frequency ADSL signal is present if the router is connected, even when no computer is being used.
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TheScullster wrote:

Yes
As long as it is synched, the carrier signals are there.
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wrote:

ADSL signals are RF. Phones are required to reject spurious RF signals. If they don't, broadcast radio (which is in the same band as ADSL) will interfere with the phone.

It may return but it sure as hell shouldn't return. Something is faulty if it does and it isn't normal to have "ADSL noise". If you have working phones you should not get noise from the ADSL even without the filters.

They may well have been faulty and generated noise but to call it ADSL noise is at best misleading.

You would get noise induced from broadcast radio too. The ADSL router would be reporting poor signal quality and throughput would be lower than expected. It may be consistent with the ADSL dropping when the upstairs phone is used as dry joints behave differently when there is DC flowing.
Has the OP tried the upstairs phone in the BT line socket behind the face plate to see what happens?
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dennis@home wrote:

Oh dear dennis.
It IS normal to have ADSL noise.
Because no wire and no connection is perfect, and down conversions into the audio band are absolutely inevitable.
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