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Author Topic: Line Fault under ADSL2+ - Prior to FTTC Install  (Read 13197 times)

WWWombat

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Line Fault under ADSL2+ - Prior to FTTC Install
« on: January 27, 2015, 01:26:49 AM »

My new(ish) line has a temporary ADSL2+ connection, while waiting for BT to sort out their back-office systems to finally get an FTTC provide to go through.

Unfortunately, this temporary ADSL connection is showing signs of some faults ... but we can't report them while the FTTC order is in place  ::) We chose to leave the order in place, and put up with the problems. Hopefully an engineer installation for FTTC will bypass the problem entirely, otherwise it may well be an opportunity to identify and fix it.

Does anyone have any advice as to what the fault might be, and what I might get the FTTC-installation engineer to double-check whilst here?

Symptoms:
- The most regular symptom is a drop in upstream SNRM when the handset is picked up to make an outgoing call. Sometimes a constant drop of 2dB through the call with no resync, sometimes a ragged drop, perhaps 5-6dB, that causes a resync (usually resulting in lower speeds).
- Occasionally, the handset being picked up also triggers a spike on the downstream SNRM graphs too.
- Occasionally, the upstream SNRM can start a period of erratic drops. No obvious trigger nor end; can trigger a resync.
- Very occasionally, the downstream SNRM joins in the period of erratic behaviour, and makes broadband access unstable.
« Last Edit: January 27, 2015, 01:30:24 AM by WWWombat »
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WWWombat

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #1 on: January 27, 2015, 01:27:49 AM »

Additionally, the Hlog graph (for just ADSL tones) shows a slight "V", which I'd normally take to be a sign of a bridged tap.

However, this "V" occurs right on the boundary between the upstream & downstream tones; as I haven't encountered Hlog graphs for so few tones before, I'm not sure whether this is a standard artefact of ADSL, or a real problem. Any opinions?
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konrado5

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #2 on: January 27, 2015, 01:43:31 AM »

This is standard artefact on ADSL. What your QLN? You have probably serious line fault, HR fault perhaps.

Best regards
konrado5
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WWWombat

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #3 on: January 27, 2015, 04:06:50 AM »

QLN looks like this, which is the kind of effect I'd expect.
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burakkucat

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #4 on: January 27, 2015, 06:52:57 PM »

Konrado5 is spot-on with his analysis.  ;D

I agree that you most definitely have a HR (or semi-conducting) joint somewhere in the metallic pathway.

The dip in your Hlog graph is nothing . . . Just consider it as a "reminder" where the US tones end and the DS tones begin, when viewing the graph from low to high frequencies!

I just hope that the person doing your install is a time-served Openreach technician and not a sub-contractor from Kelly Communications or M J Quinn.
« Last Edit: January 27, 2015, 06:56:29 PM by burakkucat »
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NewtronStar

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #5 on: January 27, 2015, 09:14:08 PM »

And a wee bit of Radio frequency Interference on tone 211 (909 Khz)
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burakkucat

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #6 on: January 27, 2015, 09:32:40 PM »

And a wee bit of Radio frequency Interference on tone 211 (909 Khz)

Which will be Radio 5.
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konrado5

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #7 on: January 27, 2015, 09:38:34 PM »

I think it is effect of HR fault, it is merely apparent Radio frequency Interferece.
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burakkucat

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #8 on: January 27, 2015, 09:48:17 PM »

b*cat nods. That certainly could be the case. The only way to be sure is to examine the equivalent graph once the fault has been fixed.
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NewtronStar

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #9 on: January 27, 2015, 11:15:17 PM »

b*cat nods. That certainly could be the case. The only way to be sure is to examine the equivalent graph once the fault has been fixed.

Or do as much as possible to the internal home broadband cable to neutralize a possible internal fault this way you can be 100% sure that the fault lies outside your premises and confident that you will not be charged for an engineer visit  :)
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WWWombat

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #10 on: January 27, 2015, 11:42:27 PM »

Thanks chaps. We'll see if anything happens tomorrow - but I suspect the job will still be built on the wrong DSLAM.

There is no internal wiring involved, so very simple from that perspective.
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NewtronStar

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #11 on: January 28, 2015, 12:13:33 AM »

WWWombat the OR engineers will do a good job, and as for line being connected to wrong FTTC cabinet if thats what your saying it would be a first as your FTTC just would'nt work, the OR Engineer will find the current FTTC/PCP cab your line is using at the moment and move you over to FTTC.

I don't know who or what has given this info that your DSLAM info will be wrong  :-\
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WWWombat

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #12 on: January 28, 2015, 09:43:04 AM »

@NS
Who has given me the info that the DSLAM data is wrong?

That would be from the 4 engineers who have been on site trying to get the basic phone line working. I've traced the line with them back to a DP shared with all the other properties on the block (flats and shops); all the lines physically go back to cab 20; all the other properties in the block have records that show cab 20.

However, our place is funny; we are in a corner property, built as part of a block along the main road, the whole block being fed by cab 20; but our entrance is on the side street, and the postal address is too - and the side street is served by cab 21. The address manages to cause confusion with some parcel delivery, and it seems to have confused the BT surveyor.

The records for this address, from first survey (September) up to last weekend, said cab 21. The records for this phone number (once working, in mid November), until this weekend, said cab 21.

The engineer who finally got the phone line working made adjustments in cab 20, then went to the MDF and re-made the connections there. Bingo - a working phone line. He gave me a copy of the PCP connection data.

All of those engineers knew the PCP record was wrong, and reported it back - but the update never made it into the back-end system. All of them knew that, with the PCP wrong, the job was then built with the wrong DSLAM, giving me a port in a DSLAM I couldn't physically be connected to.

A further engineer was sent out (in early December) with "just" the task of confirming what the actual routing was. He confirmed the route through cab 20, and gave me all the connection data. It also went back to Openreach; my ISP confirmed with BTW that the new routing data was there, and would be attached to a new order, when it was placed. It wasn't.

The 2 separate engineers (or maybe 3, I've lost count) who have only come to install the fibre portion have all immediately given up, because their job was built with cab 21. They know that FTTC wouldn't work. I knew it too. One of those was ordered to re-attend (by Openreach) later the same day, as things "would be fixed", but refused. Rightly. "Things" weren't fixed.

Today's appointment was made under the promise that the new data would be attached to it, so might work. However, the routing data (as visible in the public DSL checkers) only changed after the order was placed. We (the ISP and me) think today's order will still fail, because it is likely to still hold the wrong cab identity; we'll see.

It has been a long and sorry tale.

Even worse ... the wrong PCP is 10 yards away. The right one is 100 yards away.
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Chrysalis

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #13 on: January 28, 2015, 09:55:33 AM »

whats stopping the engineers just overuling the computer and physically connecting you to the right cab? im confused.
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WWWombat

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Re: Line Fault under ADSL2+ - Prior to FTTC Install
« Reply #14 on: January 28, 2015, 10:44:44 AM »

You mean physically connecting me to the cab in the records, so they could then connect me to the DSLAM where the port is allocated?

Simple - because there isn't a route for the copper to go to get to a DP that is connected to that PCP. I can *see* just such a DP out of the back window; it is an old-style (bell-shaped) one on the side of the next physical building along the side street (see my prev post about the layout of properties). But to get to it, the copper would have to go across a yard (not ours), a garage (ours), a footpath (not ours), a second footpath (not ours) and the garden of that building.
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