Speed Fluctuations When Phone Rings & Crackling

Ever since connecting to ADSL in January 2006 I've had a variety of technical issues and now I've just discovered another one .

A few days ago the phoneline started doing something it has never done before - crackling - which effected the ADSL, ie. loss of sync, resync, loss of sync, resync, etc. and voice calls were affected to the extent that an incoming call would not ring at all or start ringing, stop & then restart after several seconds.

The crackling was intermittent & then stopped. I neverthless phoned BT Faults to reports this, woman did a test, phoned me back and said the line was showing a fault - clicking noise and she would report it. Next day BT call back and woman on the other end says 'No Fault', starts yacking on that my equipment is faulty & then proceeds to tell me how much BT engineer visit costs if it's not their fault. Made me quite angry & was left at that.

Today phone starts crackling again round the same time as before & ADSL connection goes loopy. Quickly did some tests at the master socket test socket :


- with phone connected directly to test socket didn't seem to be any crackling

- with phone connected to test socket with current filter there was crackling

- with phone connected to test socket via replacement filter there didn't seem to be any crackling.


I therefore concluded that the filter had been playing up causing this issue. Though not 100% sure at the moment & only time will tell with the replacement.

Having replaced the filter I proceeded to check DSL diagnostics on my 2wire 2700HGV router and also dialled the BT 17070 number, option 1 - ring back to check for crackling & if calls were coming through successfully.

In doing so I noticed something strange - when the phone rings UPSTREAM CRCs begin to go up gradually when phone keeps ringing.

This then led me to do a speedtest when the phone rings - my upstream speed is effected when there is an incoming call, ie. when someone is calling but not during a conversation. This happens when the phone is plugged in or unplugged and upstream speed seems to decrease by around 20 to 40Kbps. From what I can see my DOWNSTREAM speed is fine & CRCs for DOWNSTREAM do not increase when the phone rings.

I'm at a complete loss as to why this is happening.

I'm assuming the crackling was down to the microfilter & is not associated with this latest mysterious discovery. Though if the crackling starts again then I guess it may be relevant. I'm also beginning to wonder if my LLU connection is causing either the crackling or the reduced speed when the phone rings or even both, or is it down to something else

The router is at the end of a proper hard-wired extension cable terminating at a BT style extension socket. There are 2 filters - one at NTE5 socket (where the main phone is) and one connected to the extension socket which serves the router. Ring-wire on the extension is disconnected.

I haven't had the chance to connect the router direct to the test socket without any phones connected & then call my landline via a mobile to see if DOWNSTREAM speed decreases & CRC errors increase.

Line stats are :

Fixed 1meg LLU ADSL service (since 15th October 2007)
DS snr 26dB, attn 54dB
US snr 25dB, attn 31.6dB
Router 2wire 2700HGV


Can anyone please help.

Thanks

Edited by jsf27 (Wed 12-Dec-07 21:44:10)

Well I can guess but I'm not a phone engineer...

When the phone is ringing more current is passing through the line. There is when you just lift the handset too but from what you say it seems it needs more than that for the fault to become apparent.

If there is a slightly dodgy joint in the line the higher current being passed can generate electrical noise. It sounds like some of the generated noise extends in frequency into the lower portion of the adsl spectrum occupied by the upstream but apparently not high enough or strong enough to impact the downstream.

Now whether or not BT would consider this to be a big enough fault to justify fixing is questionable but I suspect not.

Unfortunately bad joints don't get better they only get worse so I fear you are in for a period of deterioration until it gets to the point wher BT will accept it as a fault.

Sorry

Agree with Kwikbreaks, but there are a couple of things you could look at.

(1) Take you master socket out and check the connections to A and B are nice and tight. I know you are not supposed to do this but you might be in luck.
(2) if there are any junction boxes between where the line enters and the master check these as well.
Have a good listern and see if you get any crackes on normal voice use, if so, and this happens at the test socket then report it to BT as a line fault.

Many thanks for the replies & apologies for my rather long-winded post which I could have actually condensed

I didn't mention this in my initial post because I've posted the issue before here in the forum - my line does suffer from some kind of interference in any case. I've had it ever since I went onto ADSL in January 2006. This occurs with router connected directly to the test socket so obviously a BT problem.

I'm currently on a fixed 1meg connection and seeing my downstream SNR margin drop from 25dB to 9dB at times is not normal. My 2wire 2700HGV reports 'suspicious impulse noise detected' but is able to cope much better with the connection & holds the SNR unlike any other router I've tried. I did report this to my previous ISP and BT changed the line card & rejumped the connections and advised of no fault but never checked the street cabinet(s) nor the telephone pole. This didn't change things & I never requested an engineer visit as my ISP kept scaring me with the �180 end-user fault fee.

I connected my USB modem last night to test the phone ringing & downstream speed fluctuation. Unfortunately impulse noise/interference was on the line at the time & the USB modem could not cope unlike the 2wire 2700HGV and kept losing sync and even resynced at 998kbps instead of 1152kbps so the noise must have been quite bad.

When the USB modem was synced I carried out the phoning ringing & upload speed test & it was the same, so at least I know my modem/router is not at fault.

I'll do just one more test by connecting router only directly to the test socket, call the landline from another phone & conduct a speed test to be 100% sure. If the results are the same I'm going to get onto my ISP about it & also mention this impulse noise problem which has never been resolved.

Personally knowing what BT are like & what kwikbreaks has said I don't believe these issues are going to get resolved unless the line deteriorates to such a degree that BT will have to do something.

Thanks for that.

There aren't any suchjunction boxes and connections A and B were checked several months ago when I was trying to eliminate a SNR issue I've mentioned in my other reply.

> even resynced at 998kbps instead of 1152kbps

If that's so it doesn't sound like you are on a fixed speed connection. Very strange.
===
just spotted 1Mb/s UKO - sounds like it could be LLU?

I've seen reports before about audible noise on voice when a router is connected which isn't there without it. Usually this is a filtering issue but not always - the electrical noise created by a bad joint carrying adsl can sometimes be in the audio range - ie the noise isn't adsl getting through the filter to the voice kit and causing audible noise there but audio frequency electrical noise generated at the joint when the adsl signal is present.

If you get a genuine voice fault, and noise on the line is one, it's a whole lot easier getting it fixed than an adsl fault.

Edited by kwikbreaks (Thu 13-Dec-07 11:47:27)

Mmmm..... you have a point there kwikbreaks.

I assumed that the USB modem had negotiated the 998kbps sync because of the impulse interference and not being able to achieve the full 1152kbps. But that theory would point the finger to it being a 'Max' connection rather than a fixed rate

Yes it is a LLU connection with UK Online which I've had for the last 2 months. For some weird reason compared to my previous fixed 2meg IPStream it's not as good quality-wise. So another headache there

Maybe UK Online have stuck me on an ADSL2 product and fixed the rate so I get their fixed 1meg product . This might explain why the router always retrains 3 times before establishing ADSL sync - something I've never had before with my previous fixed IPStream 2000 service. Though router reports the mode as being G.DMT Annex A.

There must be something wrong with the phoneline. For example I've just resynced the router & taken a screen shot :

http://img265.imageshack.us/img265/503/ukollurouterstatsyn3.jpg

Initially stats look fine & the router even reports current maximum achievable downstream rates for my line. However suspicious impulse noise can be reported on a random basis lowering the SNRM and Max2 & Max3 can even drop to 1900kbps.

By comparison this is an example of my previous IPStream 2meg connection. You will notice that impulse noise is present affecting the SNR margin but for some reason max. downstream rates are still high. On other occasions these max. rates would also drop considerably but never below 2272kbps :

http://img264.imageshack.us/img264/9807/2700hgvbtipstream1wq2.jpg

Could I ask what significance there is if any if the downstream power changes ? It's usually around 16.8 or 17.0. Yesterday I had it fluctuating by +/- 0.3 and after a resync it reported as being 15.8.

I'll try to do my final test at the Master socket as soon as viably possibly & report back !

Thanks

> Maybe UK Online have stuck me on an ADSL2 product

LLU = UKO dslam so how they control it is their business and will be different from the BT way no doubt. My guess is that all their linecards are the same and they set what you get by the equivalent of the BT profile system.

> Could I ask what significance there is if any if the downstream power changes ?
Probably little to none. If there was only your line on the exchange they could set the power at several watts and you'd probably get maximum sync but there are other lines in the bundle so power is kept below some technically determined level to minimise crosstalk. I've seen from other stats that low sync lines are often running at lower power - guessing again - probably the "technically determined level" is set per bin (tone) and lower sync rates mean that you can't use the higher frequency bins. So less bins, same power per bin = less total power.

I hasten to add that those replies are "guesses only". If they sound convincing it is simply that I spent half my working life as a professional [censored] working for a software house (aka tech support). If they don't sound convincing then maybe I've lost my touch - I moved on some time ago.

Thanks again for the reply. Certainly what you say makes sense & can be considered as a possiblity.

Right I completed testing my connection & with the router connected directly to the test socket - filter or no filter - without anything else connected I phoned the landline from a mobile and the results are the same. Definitely a BT network fault.

Also with regards to the following pointed out by kwikbreaks :

In reply to:

---

If there is a slightly dodgy joint in the line the higher current being passed can generate electrical noise. It sounds like some of the generated noise extends in frequency into the lower portion of the adsl spectrum occupied by the upstream but apparently not high enough or strong enough to impact the downstream

---

..... I noticed something else. This afternoon when the phone rang on 2 seperate occasions it also had an impact on the Downstream - with phone ringing the downstream CRCs began to rise. When the phone stopped ringing CRCs kept going up & up from something like 10 to 10500 in a matter of 60 seconds causing the router to retrain ADSL sync due to such a considerable amount in such a short time.

Frustrated I phoned UK Online tech support & found myself getting more frustrated going through each level of support. Their tech support runs on a tier system - 1, 2 & 3 with 3 being 'proper' technical support. Instead of passing you onto the higher level each level tends to communicate like a middle-man with the next level up on your behalf & Tier 1 only passes you onto Tier 2 if they cannot help. Generally it's difficult to get to speak to someone in Tier 3, but fortunately after venting my frustration (!) at Tier 2 I got through <sigh>

I explained the CRC issues with phone ringing and the impulse noise affecting my downstream SNR margin. The guy basically said it's very likely to be a problem with the phoneline & unless the service becomes very unstable & unuseable it's pretty difficult to get BT to look into it properly which is something we all know.

Basically what he has done is switched the connection from 'fastpath' to 'interleaving' for me to see how it behaves before taking any steps to log a fault with BT. So now my delay of latency path has increased from 0.25ms to 16.00ms causing pings to go up by approx. 25ms. I'm not a gamer so no issue there but am a bit dubious about it's effect on my general usage. I've already noticed blips occuring, eg. picture downloads stalling & loading slowly on a particular website which didn't happen before.

All the interleaving has done I guess is to add some 'stability' to the connection. If the phone rings the upstream CRCs which appeared are now 'corrected' and appear as FECs which keep increasing until the phone stops ringing. As a result the upload speed doesn't fluctuate/drop.

Impulse noise protection has also been activated as my router now shows a figure of 3.12 as opposed to 0. Thought that this had made a difference to the downstream SNRM stability. However I've just called my landline and this has caused SNRM to drop from a healthy 31dB to 19dB with suspicious impulse noise being reported.

Apparently my fixed 1 meg service is a Rate Adaptive one ? I was advised this by Tier 2 support.

In my eyes activating interleaving is a DIY solution of trying to alleviate the connection of CRC errors without addressing the real cause.

As for activating impulse noise protection, well this hasn't made any difference.

The Tier 3 technical support guy said if an engineer paid a visit he would probably plug a Voyager router into the master socket and advise of no fault. Ahem..... someone is telling porkies as the engineer would surely plug his laptop/some other 'sophisticated' piece of
equipment into the test socket.

Any thoughts would be very much appreciated !

I requested interleave on my own line because of shortish periods (15 - 30 mins) of high noise levels causing problems. It can improve overall throughput sometimes and in my case does but is bad news for gamers.

I'm surprised that it has been enough to cure the resyncs - tbh I doubt that is has 100%. Only time will tell.