Just had some bad news from BT about Infinity

Just got off the phone with BT Customer Care (via their Facebook page - they're really good at responding on there) about when I might get Infinity.

The chap told me that he'd spoken to their suppliers (I assume he meant OpenReach?) who told him that my line isn't connected to a street cabinet, it goes straight to the exchange! Huh?

I told him I can see 3 BT cabinets from my front door. He suggested that maybe when my line was installed there was no spare capacity in any of the cabinets. Hardly likely as I live on an estate that has been built over the last decade and my house was one of the early phases so there should have been plenty of capacity.

He then suggested that perhaps when my house was built the cabinets weren't installed so they had to run the line from the exchange.

That sounds odd as this development has over 500 properties so surely BT would have installed the cabinets at the outset knowing that the capacity would be needed in the near future?

He said that I would have to wait until they rolled out FTTP. The only other option he said was to wait until the cabinets I can see have been upgraded then ask BT to give me a new line from one of them (subject to capacity).

So, it looks like I won't be getting Infinity anytime soon

Is it really likely that my line runs directly to the exchange? Is it more likely that their database is wrong?

The entry for my postcode in the Dec 2011 PCP to Postcode spreadsheet that someone posted in another thread is

SSTRO,TROWBRIDGE,BA148UX,{SSTRO}{M_A},1,92%,,,,

You could ask another FTTC provider and see if BT Customer Care are "mistaken".

BT Broadband's supplier is BT Wholesale.

That entry indeed says it is an exchange only post-code . It could be wrong, but not in that respect I wouldn't think.

Are they definitely BT cabinets, not VM cable? The likelihood of there being three BT ones within sight of your front door is a bit remote. I've got a few pics here. What sort of numbers do they have on them?

The roads south of 'The slipway (road)' are on PCP 64
The roads north of 'Swan Drive' are on PCP 17
The cabs outside your house day they have either of these numbers on them?

In reply to a post by RobertoS:

BT Broadband's supplier is BT Wholesale.

That entry indeed says it is an exchange only post-code . It could be wrong, but not in that respect I wouldn't think.

Are they definitely BT cabinets, not VM cable? The likelihood of there being three BT ones within sight of your front door is a bit remote. I've got a few pics here. What sort of numbers do they have on them?

Definitely not VM. I've asked Virgin if I can get their cable service and they say no - and no plans to extend their network onto our development either (even though the surrounding estates all have it).

The cabs look like the "Modern PCP outside a pub" in your photos. I'll look at the numbers some time.

As for seeing 3 from my front door, I live right on the major junction at the entrance to the development where all the major roads meet.

Just a thought you could have a exchange only line if the cabs are outside your house.
BT bring a large multicore cable from the exchange to the new estate, the split them between the two cabs, and the properties nearby are connected directly to the multicore cable back to the exchange. Hence you have a exchange only line but nowhere near to the exchange!

Are you ADSL / 2+ speeds above the norm for your line length? If so that might be a indication you have a rather good route back to the exchange DSLAM.

In reply to a post by parish:

As for seeing 3 from my front door, I live right on the major junction at the entrance to the development where all the major roads meet.

If you live in the flats on Blackthorn Way you are connected to PCP64 and will get FTTC.
The postcode you have is a bit off as it's a new build?

In reply to a post by bookey:

Just a thought you could have a exchange only line if the cabs are outside your house.
BT bring a large multicore cable from the exchange to the new estate, the split them between the two cabs, and the properties nearby are connected directly to the multicore cable back to the exchange. Hence you have a exchange only line but nowhere near to the exchange!

Are you ADSL / 2+ speeds above the norm for your line length? If so that might be a indication you have a rather good route back to the exchange DSLAM.

From my Home Hub:


ADSL line status
Connection information
Line state Connected
Connection time 8 days, 15:56:08
Downstream 3,680 Kbps
Upstream 448 Kbps
ADSL settings
VPI/VCI 0/38
Type PPPoA
Modulation ITU-T G.992.1
Latency type Interleaved
Noise margin (Down/Up) 9.1 dB / 19.0 dB
Line attenuation (Down/Up) 48.0 dB / 29.5 dB
Output power (Down/Up) 18.1 dBm / 12.7 dBm

When I first moved here 4 years ago it was closer to 5Mbps

I reckon i'm 3-3.5km as the crow flies from the exchange so about 5km line length? Seems about right for ~50dB attenuation

Edited by deleted (Thu 05-Jan-12 00:52:17)

In reply to a post by bookey:

In reply to a post by parish:

As for seeing 3 from my front door, I live right on the major junction at the entrance to the development where all the major roads meet.

If you live in the flats on Blackthorn Way you are connected to PCP64 and will get FTTC.
The postcode you have is a bit off as it's a new build?

Junction of Thestfield and Marina

In the April 2011 version of the PCP to Postcode database - http://www.google.com/fusiontables/DataSource?snapid...
- under SAU_NODE_ID it says {SSTRO}{p63} for my postcode which I took to mean cabinet 63

Ouch!

With that attenuation that is a rather low downstream connection. The higher than normal noise margin will be accounting for some of the missing speed, but the two together indicate you have a problem line. This may be addressable by you.

You are on ADSL and I would expect 4000-5600kbps connection speed. On ADSL2+ a little more, but a much higher upstream. You would also have a better BT DLM on ADSL2+ giving you a better throughput for the connection speed. Any idea why you aren't on ADSL2+?

Are you connected to the master socket, or an extension? Were the telephone points builder-installed?

There are two entries for the postcode in the latest spreadsheet set - one which is {M_A} with 92% and the other which is {P63} with 8%.

The 92% are EO lines, the 8% are connected to PCP63.

Looks like you're part of the unlucky 92%

In reply to a post by bookey:

BT bring a large multicore cable from the exchange to the new estate, the split them between the two cabs, and the properties nearby are connected directly to the multicore cable back to the exchange. Hence you have a exchange only line but nowhere near to the exchange!

And where would the two pair cable to his house be connected to the 100/200 pair cable?

In reply to a post by RobertoS:

The higher than normal noise margin will be accounting for some of the missing speed,

Surely the higher the Noise Margin (Signal To Noise Ratio) the better? High SNR and low attenuation are what you need?

In reply to a post by RobertoS:

You are on ADSL and I would expect 4000-5600kbps connection speed. On ADSL2+ a little more, but a much higher upstream. You would also have a better BT DLM on ADSL2+ giving you a better throughput for the connection speed. Any idea why you aren't on ADSL2+?

Are you connected to the master socket, or an extension? Were the telephone points builder-installed?

ADSL2+ is "up to 20Mbps" (ADSL "up to 8Mbos") yes? No idea why I'm only on ADSL, I assume it's due to the line length. I did look at changing ISP a couple of years ago and they said I could only get "up to 8Mbps".

The internal lines were installed by the builder and the four extension sockets are all next to mains sockets so I guess the internal wiring runs alongside the ring main.

When I first moved in 4 years ago I was only getting 1-1.5Mbps yet at my previous house with higher attenuation (~55dB) I was getting >3Mbps. Guessing the internal wiring was to blame I took the front off the NTE5 and connected directly to the test socket and the speed settled down to just under 5Mbps.

I've since got an i-Plate and when I fitted it the speed didn't change.

In reply to a post by Stoo:

There are two entries for the postcode in the latest spreadsheet set - one which is {M_A} with 92% and the other which is {P63} with 8%.

The 92% are EO lines, the 8% are connected to PCP63.

Looks like you're part of the unlucky 92%

Thanks for the explanation. Not what I wanted to hear, but at least it makes sense of the conflicting information.

Even when these houses were built (2002-2003) fibre BB was on BT's roadmap (IIRC they were even trialling it then) so why didn't they connect these properties so that they could easily be migrated to future technologies? I can only assume that they took the cheap option (short term profit). Any new copper layed in the last decade should be future-proof.

Despite the Govt (present and previous) banging on about eBritain and us being a world leader in BB the reality is that we are slipping down the speed tables (unless you live inside the M25 of course) because there's no proper plan in place and, despite BT not being a monopoly in theory, the reality is that the majority of the country are dependent on their network so they are still a de facto monopoly.

The Govt pland to spend £25bn on this HS2 rail line which will get used by <1% of the population, yet for half that they could fund a natiowide fibre comms network that would/could be used by >95% of the population.

High SNR margin means more stable, but generally comes at the expense of the connection speed

At low attenuations people may hit the connection speed ceiling (or are on a fixed speed product) and you can see high SNR then. There is no single rule, it depends on interpreting the many variables

A couple of years ago ADSL2+ was a lot rarer, and ADSL2+ is being rolled out by various firms all the time.
http://www.thinkbroadband.com/news/i/2846.html has a table showing that the benefits of ADSL2+ are going to be very small for you.


When you say "I've since got an i-Plate and when I fitted it the speed didn't change. " do you mean the speed remained at 5Mbps, or went back to your old 1.5Mbps

Thanks for expanding on the attenuation & SNR issues.

In reply to a post by MrSaffron:

When you say "I've since got an i-Plate and when I fitted it the speed didn't change. " do you mean the speed remained at 5Mbps, or went back to your old 1.5Mbps

It stayed at the higher speed, although my speeds have progressively fallen in the 4 years I've been here, from just under 5Mbps to ~3.5Mbps which I've always assumed was due to the increase in lines as new houses were built.

MrSaffron has explained the noise margin basics. There is further explanation in general about the SNR margin on this page, and the reason I commented on yours is to do with reasons this one.

Case 3 on that second page is what you are thinking of , and doesn't apply to your line.

As MrSaffron also says, the gain for you from ADSL2+ would not be large, but on that exchange it is odd that you are not on it. The reason is probably to do with instability, and perhaps a connection made at a noisy time. The ISP who said you couldn't get over 8Mbps was correct, but that meant the achievable speed not the technology delivering it.

So what I'm saying is that these indicators together with the other evidence suggest an actual fault or poor wiring or unusual interference from somewhere, rather than just a simple increase in other users in the vicinity.

Builder-installed wiring is often a major problem bwcause of incorrect internal cabling being used, but if it were that I would have expected poor stats from the start, not such a large decrease over time. It may be useful though if you could have a look at the back of the master faceplate and list the colours of the wires on each terminal. With the relevant terminal number as well of course.

Not sure if its been mentioned.. but what if you order a new phone line.. ?
It may be worth asking in case they can connect you to one of the PCPs of course it depends on their routing but I guess if you don't ask you don't get even if its a long shot.

In reply to a post by RobertoS:

MrSaffron has explained the noise margin basics. There is further explanation in general about the SNR margin on this page, and the reason I commented on yours is to do with reasons this one.

Case 3 on that second page is what you are thinking of , and doesn't apply to your line.

thanks for the link. Interesting reading.

EDIT: Ah, this makes it clearer, especially the second paragraph

The value reported by these, unless they give both, is never the SNR (Signal to Noise Ratio).

- I'd always taken the figure reported by the router as being the actual SNR, hence my belief than higher was better.

In reply to a post by RobertoS:

Builder-installed wiring is often a major problem bwcause of incorrect internal cabling being used, but if it were that I would have expected poor stats from the start, not such a large decrease over time. It may be useful though if you could have a look at the back of the master faceplate and list the colours of the wires on each terminal. With the relevant terminal number as well of course.

I understand that, but the internal wiring is irrelevant as I used the test socket - by which I mean I had my router permanently connected to the test socket. Having DECT phones, and hardly using the landline for phone anyway, meant that having the extension sockets disconnected was not a problem.

I only put the faceplate back on when I got the i-Plate, and if the speed had dropped noticeably with it I would have gone back to using the test socket.

Edited by deleted (Tue 10-Jan-12 10:22:12)

In reply to a post by Pgre:

Not sure if its been mentioned.. but what if you order a new phone line.. ?
It may be worth asking in case they can connect you to one of the PCPs of course it depends on their routing but I guess if you don't ask you don't get even if its a long shot.

If/when the PCPs round here get Infinity then I will try that, but TBH getting back to 5Mbps from 3.5Mbps is not really that big a deal, it's the chance of getting Infinity.

My TV has BBC iPlayer but even at 5Mbps it's not fast enough to stream HD TV so I can only watch SD on iPlayer. I read somewhere that you really need at least 10Mbps to reliably stream HD TV.

Also, I have around 12GB of free on-line storage - DropBox, iCloud, BT DigitalVault, etc. etc. - plus unlimited (yeah, yeah, I know ) storage with my web host, so remote back ups are realistic but at 448kbps backing up 10s of GB of data to remote servers is not, and no matter how fast my downstream speed is, upstream will never be greater than 448Kbps with ADSL.

So, being able to get Infinity is more important than a couple of meg boost in ADSL speed (although that would be nice).

Edited by deleted (Tue 10-Jan-12 10:11:19)

ADSL2+ should give you higher than 448 upstream connection. I suggest you ask why you aren't on it . If the exchange has only just been WBC enabled that might be it, but if it was a while ago you may just need to ask.

Well, well, well. Just got back from a week's holiday to find that the Noise Margin has dropped to 4.9dB and the d/l speed has gone up to 6016Mbps

Not that I'm complaining - far from it - but what's all that about? BT done some upgrading?