Kitz Forum

Broadband Related => Telephony Wiring + Equipment => Topic started by: jamesbob on September 06, 2020, 09:07:43 PM

Title: master socket wiring puzzle
Post by: jamesbob on September 06, 2020, 09:07:43 PM
Investigating a VDSL performance issue I ran the following DSL sync speed and speedtest.net tests in the following scenarios:


In short - the performance in the first 2 scenarios is similar, but drastically improved in scenario 3.


The following observations are also interesting:


This is puzzling because it suggests that having the faceplate attached causes significant degradation of the signal.

Is this correct?  What can I do about it?

The house is a new build, about 2.5 years old, and all the street wiring is new because the entire street is new. Does this mean the wiring in the house has been done badly?

What can I do to improve the signal to the extension socket. To be clear, there is no landline installed, and there is only 1 extension socket in a bedroom, and the only item plugged into the BT wires is a VDSL modem.

Screenshots attached if it helps diagnose the issue: (that sync speed of exactly 40000 seems suspicious...)

---

UPDATE  - I have since found that the house has a phone extension socket in every room! I didn't notice these before. They are not used. Only one socket is used for the VDSL model.


Title: Re: master socket wiring puzzle
Post by: mofa2020 on September 06, 2020, 09:38:10 PM
Maybe the extension wire is causing a problem at the master socket and makes it worse at the extension socket that could be the case as the extension (wiring or socket makes things worse), how is the extension wire connected to the master socket?
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 06, 2020, 10:24:45 PM
Good question - how is the extension wire connected to the master socket?

I'm not an expert so I don't know. Attached is a photo in case anyone more expert than myself can see.

Is this something I can fix? Or do I need to call an engineer?
Title: Re: master socket wiring puzzle
Post by: siofjofj on September 06, 2020, 10:37:47 PM
The house is a new build, about 2.5 years old, and all the street wiring is new because the entire street is new. Does this mean the wiring in the house has been done badly?
I'm afraid new build houses are notorious for having very poor telephone extension cabling in them, usually as a result of it being put in by people who don't understand the complexities of RF transmission on twisted pair wiring (which is what xDSL is). Common issues are the use of inappropriate cable (i.e. not twisted pair, but standard alarm cable or similar) or the application of 'star-wiring' (i.e. multiple extensions radiating from a central point).

Good question - how is the extension wire connected to the master socket?
The extension wiring terminals are in the cam-lock connector in the bottom left of your photo and connect to the top (IIRC) row of pins in the test socket. With the faceplate off these are disconnected, and aren't touched by anything else you plug into the test socket since standard BT plugs only have contacts on one side.. The faceplate plug is doubled sided with both sides connected together, so when you plug it in the extension wiring also gets connected to the line.

The reason this harms the broadband, even with your router connected to the master socket, is that the extra wiring can pick up interference and inject it onto the phone line. Additionally, the RF xDSL signal travels up the extension wiring, gets reflected at the unterminated end (or multiple ends if you have star wiring) and then interferes with itself when it gets back to the master socket.

Is this something I can fix? Or do I need to call an engineer?
Yes, you absolutely can fix this (and in fact should not call out an Openreach engineer since problems caused by your own internal wiring attract large charges) subject to basic wiring skills.
The first question is, do you need the extension? If not, simply remove the wires from the cam-lock connector at the bottom left of the photo, replace the faceplate, then connect your router to the master socket and all will be well. If you need the extension, we may be able to explore other possibilities with you.
Title: Re: master socket wiring puzzle
Post by: burakkucat on September 06, 2020, 10:50:52 PM
The house is a new build, about 2.5 years old, and all the street wiring is new because the entire street is new. Does this mean the wiring in the house has been done badly?

Unfortunately that is often the case. Either incorrect specification cable is used or it is incorrectly connected.

Quote
Screenshots attached if it helps diagnose the issue: (that sync speed of exactly 40000 seems suspicious...)

Ignore the "Max" and "Min DSLAM throughput" lines. Concentrate on the next two lines: "Attainable throughput" and "Current throughput". Look at the screenshot labelled "19:42 6th Sep internal master socket". (What you call the "internal master socket" is actually the test socket.) Your current throughput of 40000/9039 kbps DS/US coupled with the SNRmargin of 11 dB and 6 dB DS/US tells me a number of things:
Openreach will happily attend and fix it. But you will be required to pay the charges for time and materials. You will looking at a price in excess of 100.
Title: Re: master socket wiring puzzle
Post by: mofa2020 on September 06, 2020, 11:05:06 PM
Ok, so this test socket has pins up and down (up connected to BT lead cable and down connected to the bottom left) by removing the faceplate you are actually disconnecting the extension wire from all the master socket completely (so it is dead end where it is connected and not live on BT wiring) so it is either the extension wiring or the connection inside the extension socket that is causing the problem all the way back to the master socket...
Title: Re: master socket wiring puzzle
Post by: burakkucat on September 06, 2020, 11:08:33 PM
so it is either the extension wiring or the connection inside the extension socket that is causing the problem all the way back to the master socket...

Yes, exactly.
Title: Re: master socket wiring puzzle
Post by: mofa2020 on September 06, 2020, 11:10:16 PM
Just for info, this place is new to you so this setup as it is was not working correctly ever since you moved in?! from what I see in the master socket picture there are 3 wires connected inside the extension connector so could it be just as simple as the ring wire that from what I know can cause issues if connected?
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 06, 2020, 11:37:06 PM
Thanks everyone for the suggestions and advice - being a newbie I am learning a lot!

So I now understand that taking off the faceplate disconnects the extension cabling - which can be a cause of interference / reflection.

Sadly I can't connect the modem directly to test socket, I need to have the modem in the bedroom.

The challenge I think is therefore to reduce or remove the interference. Are there simple tests I can do to identify the cause - and what can I do about them?

I suspect changing the actual wiring might be a big project which I can't do myself.

@mofa2020 - what is a "ring wire"? Should I cut it? Do I need it for the extension wiring to the bedroom?

Would a closer photo tomorrow help anyone identify the wiring in the master socket?

Would replacing the master socket and extension socket's with better quality sockets help?


-- update

currently reading this to see if it offers any helpful remedies: https://kitz.co.uk/adsl/socket.htm
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 06, 2020, 11:46:31 PM
should I cut this orange "ring" wire ?

(see pic attached)
Title: Re: master socket wiring puzzle
Post by: mofa2020 on September 06, 2020, 11:54:01 PM
@mofa2020 - what is a "ring wire"? Should I cut it? Do I need it for the extension wiring to the bedroom?

If one of the 3 extension wires is actually a ring wire (but I am not sure it is so wait for an expert Kitzen to confirm it, or maybe I am wrong) but if it is, you do not need it at all for the modem to work in the bed room, it is just an unused wire that can pick interference (acts like antenna) and affect the DSL signal.
Title: Re: master socket wiring puzzle
Post by: burakkucat on September 06, 2020, 11:55:29 PM
If you are competent with a screwdriver and a camera then you will be able to help us help you.

Please try to perform the following steps:
Hopefully we may see sufficient detail to then be able to guide you with remedial action.

should I cut this orange "ring" wire ?

(see pic attached)

No. Please don't rush at things. Let us see the full situation, first.
Title: Re: master socket wiring puzzle
Post by: burakkucat on September 07, 2020, 12:01:57 AM
Another thought has just come to me . . . You have not yet shown us the face-plate that you have removed from the front of the NTE5C, the master socket. So please also photograph that.
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 07, 2020, 12:49:28 AM
Thanks @burakkucat - I'll do that tomorrow.
Title: Re: master socket wiring puzzle
Post by: siofjofj on September 07, 2020, 09:35:06 AM
The Fritzbox 7530 also reports "line branching" which is 2 at the extension socket, 1 at the master socket, and 0 (actually not reported) with the faceplate removed.[/li][/list]
I didn't notice this last night, but it looks like your modem has the capability to detect reflections of the DSL signal from unterminated extensions (so called bridge-taps). I have never seen this feature before, though it is certainly possible to do this by analysing the how the attenuation of the DSL signal varies with frequency. If your wiring simply went between your master socket and your extension, with no intermediate joints, there would be no bridge taps when connected to the extension, and one bridge tap when connected to the master socket with the faceplate fitted. Given that your modem is detecting two at the extension socket and one at the master (are you sure it was this way round? I'd expect the opposite) however, it looks like the wiring is more complex than that. Are you absolutely certain there is only one extension socket?

With regard to the bell wire, the purpose of this is to supply an AC coupled ringing signal to make the mechanical bells ring on old phones. As it is an unbalanced wire (i.e. not part of a twisted pair) it can collect interference which gets injected onto the line. However, modern master sockets (which yours is) connect the ring wire via an inductor in order to block high frequency junk, so this shouldn't matter in this case. As burakkucat says, leave it for now until we can see the full picture.
Title: Re: master socket wiring puzzle
Post by: Alex Atkin UK on September 07, 2020, 04:47:54 PM
However, modern master sockets (which yours is) connect the ring wire via an inductor in order to block high frequency junk, so this shouldn't matter in this case. As burakkucat says, leave it for now until we can see the full picture.

I believe the theory is the inductor reduces the problem but does not necessarily eliminate it entirely.

Personally I would have been rid of that ring wire at step 1 as there's nothing to lose by doing that, but I didn't want to tread on the toes of the people already helping in this thread.
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 07, 2020, 08:20:10 PM
I have now taken photos of the insides of the master socket and extension socket:

full resolution photos hosted on imgur


Also note that I was previously wrong about the number of extensions in the house - I genuinely hadn't noticed that there are loads! I've found 5 so far, one in every room! I'll edit the original post to reflect this.

Attached here are only some of the photos at lower resolution, for ease of use, or if the imgur links don't work after a while.

It seems the faceplate doesn't have any clever electronics to reduce noise on the ring wire.

I think, in my non-expert opinion, the fact of every room having an extension is cause for lots of noise.

Should I ask a BT engineer to move the master socket to the bedroom by going up the side of the house?
Title: Re: master socket wiring puzzle
Post by: siofjofj on September 07, 2020, 08:48:18 PM
Thank you for the images.

First the bad news:
From the photo you took of behind the master socket (attached for reference), it looks like the wiring from each extension socket terminates behind the master socket. With 5 extension sockets (which I think will be the total number, since each blue crimp connector contains 5 outgoing wires plus the one going to the terminals on the master socket), this means you have a very bad case of star-wiring, which means you have multiple bridge taps. Each extension, in particular the ring wire on each, will indeed pick up interference, but I would suggest it is the many bridge taps (or indeed the signal reflections that result from them) that is messing up your connection.

Now the good news:
Since you have access to the wires going to each socket, this should be easy to rectify yourself if you wish. Additionally, the cabling that has been used appears to be an appropriate specification (I think I can make out the text "CATEGORY 5E" on the grey outer jacket on the rightmost cable behind the master socket). Fixing this is therefore a matter of identifying which of the cables goes to the extension you wish to use for the router and separating this out from all the others. Do you need any of the other extension sockets to work, or will you be happy with only the one used for the router (both options are possible, but if you want the other extensions to work for telephones you will need to buy a centralised filter faceplate for around 15)?

Please confirm if the cable behind the master socket does have "CATEGORY 5E" written on it, and how many of the extensions you need. We'll then advise further.

It seems the faceplate doesn't have any clever electronics to reduce noise on the ring wire.
On the NTE5C, the bell wire filter (which is just a single inductor, nothing fancy) is in the socket itself, not the faceplate. In any case, as part of the repair, the plan will either be to disconnect the ring wire completely, or connect it via a VDSL faceplate (depending on whether or not you want further telephone extensions) alleviating any issues it may be causing. More on this later when we know what your requirements are.

Should I ask a BT engineer to move the master socket to the bedroom by going up the side of the house?
That is an option, but will be ridiculously expensive and more disruptive (but no better performing) than what we can achieve by rearranging the existing wiring.

Final question, do you have a multimeter? Not essential, but it will help with identifying which cable is which.
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 07, 2020, 10:18:45 PM
Hi @siofjofj - thanks for a very helpful post.

I don't need to use any of the sockets for landline phones, now or in the likely future. I think "cutting them out" of the star-wiring is the best way forward.

I have a cheap "no-brand" multimeter which I think can measure small voltages and amps .. with a pokey-sharp thing.. but I don't think it of any good quality or accuracy as it was the cheapest thing I could find on amazon years ago for a child's education project. Do I need a multi-meter to measure accurately small voltages?

Just found the item I have: https://www.amazon.co.uk/gp/product/B00YTD8CAE?

Thanks again for your generous suggestions and advice - I have a good feeling that if we can prune that star we can improve the line.

(I will have to open the master socket tomorrow to confirm category 5e, but when I last tried to check the paint seemed to cover the writing permanently)
Title: Re: master socket wiring puzzle
Post by: burakkucat on September 07, 2020, 10:51:45 PM
Sorry to be back late to your problem. (I had a bad night, last night and today things took longer than I would have liked.)

I've reviewed all of the photographs and agree with siofjofj's analysis.

As for your multimeter, that looks perfectly acceptable. You will only be dealing with a DC voltage in the order of 50V and a maximum current of the order of low double-digit mA.
Title: Re: master socket wiring puzzle
Post by: siofjofj on September 08, 2020, 07:56:42 AM
OK then, if you only want the one extension this will be straightforward. Don't worry too much if you can't read what the cable says on it, I can see that it is twisted pair from the photos so is likely good enough even if it is not CAT5e (CAT5E is significantly better than what is required, the minimum being CW1308 telephone cable).

First, make sure you know which pair of wires are the ones going to the A & B terminals on the back of the master socket. Be very sure not to accidentally cut these as they are not your property, they belong to Openreach. You should be able to gently pull all the other wiring forward slightly and untwist things in order to improve access. You will note that each grey cable has a solid blue wire, a solid orange wire, and a blue with white stripe wire (plus a bunch of other wires which have been cut off flush with the cable end). Remove the existing three wires from the three cam-lock* terminals on the front of the master socket.

The task now is to identify which of the five outgoing cables goes to the extension socket you wish to use. Then connect the solid blue wire from that cable (only) to terminal 2 on the front of the master socket and the blue with white stripe wire (from the same cable) to terminal 5 on the front of the master socket. The solid orange wire and corresponding terminal 3 are for the ring wire and should be left disconnected.

There's a few ways of identifying which cable is which. The simplest would be by trial and error, so just cut all the wires out of the crimp terminals, wire up a single pair to the front of the master socket, replace the faceplate, then see if a telephone works at the extension socket you want (could also try all the other extensions then label all the wires in case you change your mind in years to come). If you don't have a telephone this last step could be done by checking for around 50V DC across terminals 2 & 5 behind the extension socket, but don't use your router to test it at this stage as repeated connections and disconnections can lead to Openreach's equipment thinking your line has a fault and banding your connection as a result.

Another technique you could use, if you would prefer not to separate out all the wires, would be to short the spare green and green with stripe (say) wires together at the extension socket, then check for continuity between these spare wires behind the master socket using your multimeter. Once you have located it, then simply cut out the relevant blue, blue with stripe and orange wires from the crimp terminals and wire up the blue ones as above.

When wiring up the terminals, try to keep the blue and blue with stripe wires twisted together (in the same way the spare pairs behind the extension socket are) over as much of their length as possible.

Once this is done, tidy up the cut wires somehow towards the back of the box, replace the master socket, replace the faceplate and connect your router to the extension (no filter required here if you don't use a telephone at the extension). Please let us know the result.

* These cam-lock connectors work by hinging them up from the bottom. Once it is lifted, you can pull the wires out. To install new wiring, insert straight pieces of wire into the relevant holes (without stripping any insulation) then fold the connector back down. The connector contains metal teeth which will cut a hole in the insulation as you fold it down in order to make contact.
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 08, 2020, 02:26:43 PM
Thanks @siofjofj this is really helpful - I'll certainly have a go.

Are there any web pages out there which have pictures/photos to doing this at all - I think if I can "see" what I'm doing, it would help a nervous amateur like myself.


Title: Re: master socket wiring puzzle
Post by: siofjofj on September 08, 2020, 02:46:22 PM
I generally use the diagram under the blue header "The Wiring" on this page http://www.wppltd.demon.co.uk/WPP/Wiring/UK_telephone/uk_telephone.html (http://www.wppltd.demon.co.uk/WPP/Wiring/UK_telephone/uk_telephone.html) for reference. I'll try and draw up something specific to your situation shortly.

There's some instructions for operating the cam-lock connectors here (ignore the 2nd section on the Mk4 VDSL filter since we are not using that here) https://www.openreach.co.uk/orpg/home/helpandsupport/how-toguides/howtoguides/downloads/NTE5C_Instructions_CP.pdf (https://www.openreach.co.uk/orpg/home/helpandsupport/how-toguides/howtoguides/downloads/NTE5C_Instructions_CP.pdf)
Title: Re: master socket wiring puzzle
Post by: siofjofj on September 08, 2020, 03:26:24 PM
OK, I hope these are useful. The first one, 'Current.png' is a diagram of how I believe your wiring is currently connected. The second 'Target.png' is what we are trying to achieve. The wiring to the unwanted extensions obviously does not have to remain in the crimp terminals if you want to separate everything out first in order to go for the 'trial and error' technique, the point is that none of it should be connected to the telephone line.
Title: Re: master socket wiring puzzle
Post by: burakkucat on September 08, 2020, 05:12:59 PM
Just "purrfect" instructions. If I didn't already know my way around the topic, wearing a blindfold and asleep, the diagrams make it all absolutely clear.

There is one thing I would be very tempted to do -- especially if I still had the extension socket de-mounted from its backing box -- and that would be to remove the orange wire from IDC3. (Ye olde and redundant belle wiree.)
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 08, 2020, 06:05:37 PM
hi @burakkicat do you mean remote the ring wire from the extension socket as well, in addition to the master socket? .. which I makes sense as it would be an "aerial" picking up interference at the extension socket too.
Title: Re: master socket wiring puzzle
Post by: burakkucat on September 08, 2020, 07:24:59 PM
hi @burakkicat do you mean remote the ring wire from the extension socket as well, in addition to the master socket?

Yes, that's correct.
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 08, 2020, 11:14:08 PM
ok - I will have a go this weekend.

(I won't attempt it this week as I need the internet for work... )
Title: Re: master socket wiring puzzle
Post by: burakkucat on September 09, 2020, 12:05:59 AM
I've just taken another look at the wiring at the extension socket (shown in reply #16) (IMG_20200907_194729.jpg) and noticed that there is also a redundant wire attached to IDC4.  :-[

So both wires, the orange (IDC3) and the white with orange stripe (IDC4) can be removed. Don't cut them, just gently pull them out.
Title: Re: master socket wiring puzzle
Post by: siofjofj on September 09, 2020, 08:26:59 AM
Just "purrfect" instructions. If I didn't already know my way around the topic, wearing a blindfold and asleep, the diagrams make it all absolutely clear.
Thanks very much! That's quite the complement.

I won't attempt it this week as I need the internet for work...
A wise plan, though remember if you get stuck at any stage you will still be able to access the internet by connecting your router to the test socket, at which point you will be able to send us more photos and ask for further advice.
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 12, 2020, 07:02:41 PM
So I made a start .. but have run into a problem.

From the extension socket I removed the orange (IDC3) and white-orange(IDC4) and tested the DSL sync. This seemed to improve the sync from 27-28 earlier in the day to 29.9 Mbs. Of course this could be normal variation but I check the sync before and after. So the looked positive. I

I then opened the master socket and removed the connections to the transparent wire connector (the one that cuts through the rubber when shut), and unwound the many bundled wires. Sadly the advice to flex/bend the blue wire holders didn't work as they seem to be "pressed" to cut through the wires. So I had to cut the wires.

I then had to check all 36 combinations of 6 blue and 6 white-blue wires.. up and down the stairs between the master socket and a test phone for a dial sound. Sadly no sound in any combination. This puzzles me.

So I then shorted the IDC2 and IDC5 to check which combination of wires at the master socket would result in almost zero resistance.

As it happens there is only 1 combination that does this - which means I found the correct blue and white-blue wire that leads to the desired extension socket.

Sadly - when connected using the transparent wire connector, there is no DSL signal and no phone dial tone.

I did try other combinations just in case and no dial tone and no DSL signal. I didn't try all 36 combinations with the DSL but I did with the phone - no dial tone.

Any suggestions? I feel a little lost for ideas to try as what we did seemed very logical.
Title: Re: master socket wiring puzzle
Post by: siofjofj on September 12, 2020, 07:11:59 PM
From the extension socket I removed the orange (IDC3) and white-orange(IDC4) and tested the DSL sync. This seemed to improve the sync from 27-28 earlier in the day to 29.9 Mbs. Of course this could be normal variation but I check the sync before and after. So the looked positive.
Sounds reasonable.

I then had to check all 36 combinations of 6 blue and 6 white-blue wires.. up and down the stairs between the master socket and a test phone for a dial sound. Sadly no sound in any combination. This puzzles me.
There should be no need to try all 36 combinations. There are 5 (6? are you including the original wires between the crimp terminals and master socket?) grey sheathed cables entering the back box of the master socket, each containing a blue, blue with stripe and orange wire (plus some other ones, but they have been cut off). The pair you need will share a single sheath. Double check that this is the case for the wires you have connected. It sounds like a simple mistake has been made and you've connected one wire from two different cables. Remember the faceplate needs to be put back on the master socket to connect the extension wiring.

So I then shorted the IDC2 and IDC5 to check which combination of wires at the master socket would result in almost zero resistance.

As it happens there is only 1 combination that does this - which means I found the correct blue and white-blue wire that leads to the desired extension socket.
Please double check this. If you have DC continuity between the master socket and extension the phone (at the very least) should work. You could also check for 50V DC between terminals 2 and 5 at the extension, or even better the voltage between terminal 2 and ground and then terminal 5 and ground (this may give us some idea if one terminal is connected but not the other).
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 12, 2020, 07:45:24 PM
SUCCESS!  :)

It seems replacing the master socket faceplate did the trick. I was surprised as looking at the faceplate theres't nothing there other than moving the connection vertically up internally.

Listening to the dial tone on the extension socket gave no normal dial tone - but instead gave quiter faster higher-pitched "clicks". About 3 or 4 per second. Is this something to be worried about? We're not going to use landlines so this question really is about safety - am I burning any components?

Anyway - the DSL synced at almost the master test socket rate. Modem reporting current throughput 40Mbs down and 9.2 up.. and speediest giving 37 and 8 Mbs .. which is a massive improvement. The frequency spectrum is also "full". Previously at the extensions the higher frequencies were being filtered out.

The modem also isn't reporting any "branching" which is also good.

THANKS EVERYONE - I think this should be listed as a real success of people helping each other. Myself, I've barely changed a lightbulb! (I do have a physics degree so I know what volts are but I've never done it practically)

I'll post again a few days time to hopefully confirm all is well!

 :)
Title: Re: master socket wiring puzzle
Post by: siofjofj on September 12, 2020, 08:02:22 PM
It seems replacing the master socket faceplate did the trick. I was surprised as looking at the faceplate theres't nothing there other than moving the connection vertically up internally.
The plug on the faceplate has contacts on the top and bottom of it which are connected together. The test socket also has two sets of contacts, with one set connected to the incoming line and the other connected to the cam-lock terminals. When you install the faceplate the two are connected together. This is the whole point, so that when the faceplate is removed all your internal wiring is disconnected so that Openreach can verify their own wiring without including your own (making the socket the 'demarcation point'). You can see in much more detail how the socket works here https://www.youtube.com/watch?v=CkFMfB-DYmQ (https://www.youtube.com/watch?v=CkFMfB-DYmQ) and what is inside it here https://www.youtube.com/watch?v=jD67a-ZC7VY (https://www.youtube.com/watch?v=jD67a-ZC7VY).

Listening to the dial tone on the extension socket gave no normal dial tone - but instead gave quiter faster higher-pitched "clicks". About 3 or 4 per second. Is this something to be worried about? We're not going to use landlines so this question really is about safety - am I burning any components?
Is this perhaps the stuttered dial tone you get to tell you someone has left a voicemail message (call 1571 to pick it up and delete it if so)? If not, I'd say this doesn't sound right. There won't be anything dangerous here that's going to cause damage, but there could be a bad connection which could end up messing up your DSL connection later if it gets worse. Call 17070, select option 2 (quiet line test) and have a listen. The line should be completely silent.


Anyway - the DSL synced at almost the master test socket rate. Modem reporting current throughput 40Mbs down and 9.2 up.. and speediest giving 37 and 8 Mbs .. which is a massive improvement. The frequency spectrum is also "full". Previously at the extensions the higher frequencies were being filtered out.

The modem also isn't reporting any "branching" which is also good.
Excellent, congratulations on your improved service. It sounds like all the bridge taps have now been eliminated. It looks like you have interleaving applied to your line (hence the 8ms delay on the downstream). If you now leave the modem connected and undisturbed, with a bit of luck, this will be removed over the coming days/weeks which should give you slightly lower latency.

THANKS EVERYONE - I think this should be listed as a real success of people helping each other. Myself, I've barely changed a lightbulb! (I do have a physics degree so I know what volts are but I've never done it practically)
You're very welcome, and I'm pleased you got a good result. I believe there's quite a few physicists here (myself included)!
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 12, 2020, 08:20:50 PM
The phone service isn't actually provisioned.. as in we don't pay for a voice call service. So there shouldn't be any voicemails.

Because there isn't a voice service is expect I can't call 17070.

I'll leave it a couple of days and report back.
Title: Re: master socket wiring puzzle
Post by: siofjofj on September 12, 2020, 08:26:25 PM
This would be very unusual. Who do you pay your line rental to? The only provider I know of that offers 'naked DSL' without a phone service is Andrews & Arnold. For pretty much everyone else you should still be able to make and receive calls, with outgoing calls charged on a 'per minute' basis since you don't have a call package. Regardless of what you have, 17070 will still work, and is free, since this is a test number Openreach use to test and identify your line.

I should also have asked the obvious question, do you also get this stuttered dial tone at the test socket?
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 12, 2020, 09:33:06 PM
yes - it's zen, so not a naked DSL line. There is a number, but no call package.

I'll test the master socket again tomorrow with the handset to see what the tone is like.

So far the internet is working fine.
Title: Re: master socket wiring puzzle
Post by: Alex Atkin UK on September 12, 2020, 09:38:06 PM
Also looks like you have downstream interleaving, I'd expect that to go away over time as the DLM system sees your line problems have been solved which will improve latency by 8ms.

There certainly seems to be some leeway there to go slightly faster too if you felt it was worth going for a higher package.
Title: Re: master socket wiring puzzle
Post by: jamesbob on September 12, 2020, 09:56:40 PM
what is "interleaving" ?

is it an error correcting method that BT uses adaptively for noisy / poor lines?
Title: Re: master socket wiring puzzle
Post by: siofjofj on September 12, 2020, 10:02:02 PM
what is "interleaving" ?

is it an error correcting method that BT uses adaptively for noisy / poor lines?
Essentially yes. It is part of all the xDSL standards (so usable on any and all operators equipment) and improves the effectiveness of the 'Forward Error Correction' (FEC) algorithms at the expense of additional latency. The FEC algorithms themselves also add some overhead, slightly reducing speed too. Openreach's DLM has enabled it on your line, likely because of your wiring issues. You can read all about it here https://kitz.co.uk/adsl/interleaving.htm (https://kitz.co.uk/adsl/interleaving.htm). As Alex says, now the DLM can see your line issues are resolved (assuming there isn't some other issue) hopefully it will get turned off.