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Author Topic: master socket wiring puzzle  (Read 1369 times)

jamesbob

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Re: master socket wiring puzzle
« Reply #30 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.
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siofjofj

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Re: master socket wiring puzzle
« Reply #31 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).
« Last Edit: September 12, 2020, 07:16:34 PM by siofjofj »
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jamesbob

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Re: master socket wiring puzzle
« Reply #32 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!

 :)
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siofjofj

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Re: master socket wiring puzzle
« Reply #33 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 and what is inside it here 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)!
« Last Edit: September 12, 2020, 08:17:33 PM by siofjofj »
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jamesbob

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Re: master socket wiring puzzle
« Reply #34 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.
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siofjofj

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Re: master socket wiring puzzle
« Reply #35 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?
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jamesbob

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Re: master socket wiring puzzle
« Reply #36 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.
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Alex Atkin UK

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Re: master socket wiring puzzle
« Reply #37 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.
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jamesbob

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Re: master socket wiring puzzle
« Reply #38 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?
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siofjofj

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Re: master socket wiring puzzle
« Reply #39 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. 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.
« Last Edit: September 12, 2020, 10:04:12 PM by siofjofj »
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