very poor service and a warning re 21cn "upgrade"

[#1]

Nope it won't mess things up, and I hadn't assumed you were a pleb or anything of the sort and you can tell your friend they are welcome to stay in suburbia 
As regards the other wiring, well it depends on the cable standard - as long as it is all cable to CW1308 spec. and only the Blue/white trace and White/blue trace are the only ones connected, to terminals 2 & 5 throughout, it shouldn't be a problem. As you've already said plugging in the test socket makes no difference I suspect it may be ok. But if you need to look at it to check, best to do so when you've powered down to swap modem/routers. It would be worth checking along the cable runs just to be sure no physical damage has occurred and preferably no power cables are running parallel especially closer than 6 inches.
I'll PM you later with some info. Oh yes, totally agree about today's bloatware!

[#2]

Quote

On 21CN you can be set at ADSL1 mode at the exchange which can give a more stable connection as it won't event try to use the higher frequencies of ADSL2(+),. so again something to consider.

If that is thought useful following current tests, then from a look at the TD-W8960N manual it looks like it might be possible to force ADSL1 mode at the router. Looking at page 60 you can select which modes are available, by disabling all except G.DMT it should effectively force ADSL1. I'm not sure if that would be any different from forcing at the exchange but it certainly would be easier to try if necessary.

[#3]

I know some modem/routers have the ability to do that but I have absolutely no idea how it will behave, especially on a longish line. Certainly might be worth a try later on. If needed, Plusnet can get it done at the exchange without any real problem.

[#4]

i have a bit more info.
line distance, measured using odometer: 0.9miles overground(believe this has all been replaced in last 2-3 years after storm damage) remainder underground so not sure which route it takes. most likely scenario gives a total of 2.75 miles to the exchange and the least likely (alongside an open mine) adds 0.25 miles. surprised to see overhead line cutting the corners -underground?? - have not allowed for this just measured the whole route by road.
a bit annoying to see "infinity is here" all over the exchange box! - have checked and nothing planned to for  it to arrive at my local box in next 6 months - they implied it is likely to be much longer, ie 2 years!!
telephone conn, cant tell which specific pairs are used without removing master faceplate which i am reluctant to do (see later) conn in telephone skt is as follows:
1 green+white
2blue+white
3orange+white
4 white+orange
5 white+blue
6 white+green
have looked at router and under advanced settings:DSL-
all but annex M enabled
phone lines inner pair selected
bitswap is enabled
will avoid any changes at this stage see below.
Had an update from plusnet, someone has kindly taken up the cause and noticed that the loop line loss is varying by up to 10dbs, appears to occur after each bt visit. they have now requested a bt boost engineer to attend and check line more thoroughly inc my internal stuff. visit is booked for Friday am so watch this space- they have suggested that i shouldnt hope for too much but who knows. whats interesting is that we currently have a dry spell which is forecast to last the week and this is usually when the line starts to exhibit problems. shine on i say!!

[#5]

Right ok, that all sounds more promising.
Are you going to swap modem/routers, because whilst you are off-line will be the time to deal with this wiring. In a broadband situation you only need terminals 2 & 5 connected as I mentioned in reply #15. The surplus wiring - the "bell" wire on terminal 3 especially as it's connected to one leg of the line via the ring capacitor, picks up interference. So all the others except 2 & 5 should be pulled vertically out of the IDC terminals at all sockets, but do the master first. Be careful not to disturb 2 & 5 and make sure that they are firmly down in their IDC terminals. Do not use a screwdriver in the terminal itself as it may open the jaws and give a bad connection. Coil the removed wires out of the way at the back of the box so as not to come into contact with any terminals.
Unless they've already been disconnected at the master, you should see an immediate benefit and improved sync speed when you reconnect.

[#6]

planning to stick with current router and not disconnect until the BT "boost" engineer visits friday - i want to keep the connection stable for as long as possible. he has been given very specific instructions this time on what to check and to liaise with plusnet during the visit if possible. (anyone know what a boost engineer is? i wouldnt want that title!)
also planning to see if the snr and line loop loss varies as the dry weather continues over the next 3-4 days. hoping that the more data i can present the more seriously they will take the problem.
regarding the wiring. im pretty sure (from memory) that only the blue/white and white/blue wires are connected at the master skt. plan to check this when bt visit, also plan to try zoom router again after visit if it hasn't shown any improvement after a couple of days and/or the line loss loop is still high.
have tried to follow internal wiring but virtually impossible. may explore removing all extensions and connecting phone and adsl at master skt - cant see how this can make things worse.
i  can say for sure that power runs are close to extn wiring, especially as skts are adjacent on the wall in two places!

[#7]

Hi toutlemonde,
I'll be interested to see how it goes after the engineers visit. I've seen other people get better results with certain routers on longer lines. I'm sure someone on here could recommend one for you.
Jojo

[#8]

so the bt engineer visited, spent 2.5 hrs at house and exchange. claimed to have found a "slight fault" at the exchange but would not explain.( i did press, believe it was to "comfort me" !!)
prior to visit i had monitored line at regular times and, as expected with the fine weather, the characteristics changed. the primary change was the snr downstream which dropped from average of 6dbs to 2.5dbs, this in turn increased the dstream speed from 500kbps to 1120kbps.
apparantly this was giving lots of dropouts( i never saw any) so bt insisted on fixing the line at 6 dbs ( noticed that it does vary by +/- 0.5dbs) many line tests carried out and eventually left with a line speed dstream of 690kbps. this does not vary much but page download toie varies considerably depending on time of day. very concerned now as to what will happen when the wet weather returns and the line attenuation increases.
i asked about reverting to 20cn (adsl1) and was told its not possible under any circumstances. when questioned about sacrificing  upstream speed for improved downstream speed he had never heard of such a thing. ]]the eng was unable to give details of actual line lengths but claimed his "tests" indicated it was nearer to 6km rather than the 4.4 km max i measured - it would basically have to go in the wrong direction for some considerable distance..
so bt and plusnet claim NO more can be done. I have informed plusnet that i intend to proceed with my formal complaint so will probably have to stop updating on progress on this subject, ( misleading information regarding 21CN "upgrade"), but happy to pursue more technical solutions.
can confirm only the blue/white wire pairs connected.
currently monitoring the line, but over the next 48hrs i will attach other routers and post data from them. switching in theory should not have much effect as they supposidly have "fixed" my line attenuation!

[#9]

Well not only did he sound like he wasn't a very helpful engineer (did you offer him tea and biscuits?) but it sounds as though his knowledge of broadband was somewhat limited. Clearly if more bandwidth is given to the Upstream there is a little less for the Downstream.
On 21CN the line can be set to ADSL1 mode as previously said, this is not 20CN - the engineer (not) could have explained that if he understood it himself, however I'm not convinced that is the best way to go at this point. Capping the Upstream should be the first move.
(Just to point out you would have been moved to 21CN at some point in any event as once an exchange is upgraded the obsolete 20CN equipment will be decommissioned and removed).
Please post the latest ADSL line stats. Don't forget to use the disconnect procedure I outlined in reply #4 if swapping things about.
The attenuation should not change at all, you may get a minor variation (+/-1dB) as longer term average temperature changes. You do tend to get slightly different readings from different modem/routers. If attenuation varies when it is wet, there is a line fault somewhere.
The SNRM can vary between daylight and night time due to increased LW/MW propagation after dark, however if the line is properly balanced, only terminals 2 & 5 are connected at all sockets, the correct standard of cable is used and most of it is underground, these are variations are usually no worse than a couple of dB and often less.
This is not the same as the Target SNRM which is in 3dB steps. The exchange DLM will start with a 6dB figure and will reduce to 3dB on 21CN if conditions permit (conversely it will go the other way if there are line problems). Banded speeds is another constraint DLM can introduce.
Can you look at the BT incoming cable, does it arrive underground or overhead, and see if it has a Black sheath, round cross-section about 5.3mm in diameter.?
I don't think I've asked before but have you heard/can you hear any crackling or other noises on the line when using the phone?
(I've sent you a PM as well).

[#10]

latest router stats using tp link
Mode: ADSL_G.dmt.bis
Traffic Type: ATM
Status: Up
Link Power State: L0

Downstream Upstream
Line Coding(Trellis): On On
SNR Margin (0.1 dB): 64 62
Attenuation (0.1 dB): 750 457
Output Power (0.1 dBm): 0 128
Attainable Rate (Kbps): 1180 440

Path 0 Path 1
Downstream Upstream Downstream Upstream
Rate (Kbps): 800 440 0 0

MSGc (# of bytes in overhead channel message): 59 12 0 0
B (# of bytes in Mux Data Frame): 25 55 0 0
M (# of Mux Data Frames in FEC Data Frame): 8 1 0 0
T (Mux Data Frames over sync bytes): 1 1 0 0
R (# of check bytes in FEC Data Frame): 16 8 0 0
S (ratio of FEC over PMD Data Frame length): 8.0 4.0 0.0 0.0
L (# of bits in PMD Data Frame): 224 128 0 0
D (interleaver depth): 4 8 0 0
Delay (msec): 8.0 8.0 0.0 0.0
INP (DMT symbol): 1.14 2.0 0.0 0.0

Super Frames: 10990780 601163 0 0
Super Frame Errors: 0 0 0 0
RS Words: 89300094 2499442 0 0
RS Correctable Errors: 246918 4294967254 0 0
RS Uncorrectable Errors: 16401 0 0 0

HEC Errors: 4294967282 4836 0 0
OCD Errors: 109 0 0 0
LCD Errors: 0 0 0 0
Total Cells: 336964039 917976 0 0
Data Cells: 2912790 20684 0 0
Bit Errors: 0 0 0 0

Total ES: 64934 4294967295
Total SES: 234 0
Total UAS: 2217 744
the bt eng was helpful but only recently out of his apprenticeship - and most of that was on the job, hence he had to keep referring back to base. had already discovered adsl1 was not the old 20cn but dont think plusnet are interested in this option. you are right that eventually i would have had to switch but would have preferred to leave it as long as possible with hindsight. my primary beef is that despite asking the right questions i was given completely misleading and wrong information and as such i would have held off on the switchover. i also think that bt should be forced to explain this so called "upgrade" which is totally inappropriate for an area such as Cornwall where a high percentage of rural users will find themselves worse off - i suspect the "upgrade" is for bt to make cost savings! anyway enough of the soapbox stuff....
to answer some of your questions:
bt cable arrives at my house overhead on a pole and then travels underground to enter the house. it is a round black sheathed cable about 5mm as you describe.
the line has crackled in the past and we have had bt out twice this year for this problem. it has also completely failed once- apparantly blown fuse in the exchange. we also used to get an echo/feedback noise when the line snr was down to less than 1db, not heard this recently.
are you suggesting i remove all the extn wires except 2 and 5 even though only these two are connected at the incoming master skt?
currently getting small bouts of rain here so monitoring current router to see if snr varies. currently variation on snr dstream is from 5.7 to 6.7dbs and 6 to 6.9dbs upstream. have already noticed that snr is varying in 3db steps generally on this system, unlike previous 20cn. as you say variation otherwise is keeping to 1db or less. will see how weather affects this.
regarding capping upstream speed, guess this is something plusnet have to do. presumably this must have some affect, especially if streaming for iplayer etc as i was surprised to find for every 200mb dload it requires 8mb upload - presumably for error checking - much higher than i would have expected.
will see how stats very today and try different routers tomorrow.

[#11]

It seems your line in it's current state cannot support a sync under ADSL2+ line conditions, denoted by the fact it's currently trained in ADSL_G.dmt.bis mode, which is ADSL2. As MisterW stated earlier in this thread, you can at least try an ADSL1 sync (which is what you had prior to your problems) by adjusting the settings in your router.

Quote from: MisterW

If that is thought useful following current tests, then from a look at the TD-W8960N manual it looks like it might be possible to force ADSL1 mode at the router. Looking at page 60 you can select which modes are available, by disabling all except G.DMT it should effectively force ADSL1. I'm not sure if that would be any different from forcing at the exchange but it certainly would be easier to try if necessary.

By doing this you will at least be able to see if you can get an increased sync under those conditions, before requesting PN to make a change via BTO to the hardware in the exchange. If it does not improve the situation you can always revert back.

[#12]

Hi toutlemonde,
I could put you on ADSL1 on 21CN  which works pretty similar to 20CN
Jojo

[#13]

Hi toutlemonde,
Well, the BT incoming cable seems to be the correct standard.

Quote from: toutlemonde

are you suggesting i remove all the extn wires except 2 and 5 even though only these two are connected at the incoming master skt?

Yes. Even with the Rat's tail filters, there are often all 4 cores of the cable crimped in the plug and although only the A&B wires may actually be connected in the filter, there could still be coupling effects albeit small, and as you are on a very long line I would want to minimise the chances of that to as near zero as possible.
My bold in the quote

Quote from: GrahamC

...................... you can at least try an ADSL1 sync (which is what you had prior to your problems) by adjusting the settings in your router. By doing this you will at least be able to see if you can get an increased sync under those conditions, before requesting PN to make a change via BTO to the hardware in the exchange. If it does not improve the situation you can always revert back.

Not quite true Graham, don't forget 21CN DLM is more aggressive than 20CN, and yes whilst it's worth trying by altering settings on the modem/router, I doubt sync speed will be any higher as there won't be any more tones available, although stability may improve.
I'd be interested in trying to see what the bits/tone allocation was currently like and ensuring there aren't noise problems before making the change Jojo has suggested.
@Jojo
Changing to ADSL1 mode is something I presume you have to do by placing an order with BTw? or is it something you can now change there at Plusnet?

[#14]

Quote from: Anotherone

Changing to ADSL1 mode is something I presume you have to do by placing an order with BTw? or is it something you can now change there at Plusnet?

Yes, I'd place an order but it only takes 24 hours to change.

[#15]

thanks all,
i have raised some of your ideas/comments with plusnet on my fault ticket. specifically the ADSL1 and capping upstream speed issues. i have asked that no changes be made until they state what if anything this will do for me.
interested to see Jojo's response on adsl1 switch also. please dont do it until i get a formal response from plusnet team, not sure how the relationship works here? just seen your reply - so if change is done in 24hrs how long to settle before we know if it has improved the speed and how long to change back again?
will look at internal wiring and see what i can do to minimise it.
currently having thunder and lighting so not switching router yet. this was not forecast for cornwall. interesting comments from last three openreach engineers - they are all pretty pissed at cornwall getting subsidy for infinity upgrade. irony of it is that very few people are going to be able take advantage since rural users here must be at least 50% of total. the box in gunnislake with infinity close to the exchange, has very very little take up and until it rolls out to all the other conn boxes within in a 1-2 mile radius it will remain so - and there are no plans for this!
stats are pretty static.(since bt visit) snr d/stream range is 5.7dbs to 6.7dbs and speed 680k to 700k, ip threshold gradually dropping 1252 - 1140kbps
upstream snr 5.8dbs to 6.9dbs, speed 360k to 370k all other parameters the same.
thanks for personal message Anotherone, will look at down loading lite version- presumably to get continuous stats the computer has to remain on, or are they collected remotely?