BT Inifinity 1 Installed Today, Some Advice Please

Hi All,

Well, after some problems with the order system at BT, I've finally had 'fibre' enabled this morning, which is good thing.

The queries I have are to do with line speed and the training period.

When I ordered BT Infinity 1, I was told I would receive 16.1 Mbps and have a minimum guaranteed line speed of 14 Mbps.

Unfortunately, checking the specs, I am connected around 11500 kbps (can't remember the exact figure as now at work) and had a download speeds of approx. 10.1 (from Think Broadband and BT Speedtester). I appreciate compared to my old stats of 6.1 Mbps and 8128Kbps (line sync) this is an improvement but not really for the additional £10 price premium..

Anyway, my questions are:-

1.) Does anyone know if during the training period my line could re-sync at a higher level?

2.) If the line sync doesn't raise above the minimum guaranteed speed, what happens then? Can I go back to ADSL? Would BT make me remove the fibre and go back to ADSL? Would I be made to keep my 12 month contract?

At the moment, BT won't help as they say I have to wait a full 10 days for line training.

1) No. Other than the variation between sync's you get on ADSLx, but a bit bigger.

2.2.1 Dynamic Line Management

Dynamic Line Management (DLM) is employed in GEA-FTTC. DLM constantly manages lines to maintain a target link quality (speed and stability). It does this for as long as the product exists.
At provision, the line is put on �wide open� VDSL2 line profiles allowing the upstream and downstream line speeds to run at the upper limit of the product option selected.

BT SIN 498.

BT Wholesale talk rot about the ten days. Always did, and on FTTC it has never had any effect whatsoever on speed.

Edited by RobertoS (Tue 24-Nov-15 14:01:50)

Did you have an engineer install? If not, have you checked your internal wiring isn't causing issues?

If everything is as it should be with your wiring then you should be able to break the contract as they aren't meeting the estimated speeds given at sign up.

If you have any extension sockets (and they aren't centrally filtered), then I always recommend in situations like this you baseline the performance by getting stats using the test socket. Assuming you have a modern master socket what you have to do is unscrew the faceplate and detach it which will both isolate extension wiring and reveal the test socket underneath. Note that this isn't the permanent arrangement, but just a way of finding out what optimal performance is.

Note that even if the HH% is attached to the master, any extensions not filtered at the master will impact VDSL performance.

One issue is not to do to many connections/disconnections as this can put DLM into something of a tizzy which


I assume you are doing your benchmark tests using a wired connection, not WiFi.

I'd also recommend getting the line stats out of the HH5 (go to trouble shooting and then "heldesk"). The sync speed, attenuation and SNR margin can provide information over whether you are in the right ballpark. If the target SNR margin has been set high or interleaving is turned on by DLM then it will have a material impact.

Do you have those guarantees in writing?

And what does the DSL checker say for Clean and Impacted? http://www.dslchecker.bt.com/adsl/adslchecker.welcome

Thank you all for taking the time to reply.

I do have the BT HH5 plugged directly into the master socket, I don't have any extension wiring. I tried plugging HH5 into the socket (after unscrewing the font face plate) this made no difference, still the same snyc rate.

This was a self install.

The data rate from my HH5 is :- 1225/11724

In reply to a post by MHC:

Do you have those guarantees in writing?

Yes, in an email order confirmation BT sent to me

How fast?
We estimate your download speed will be between 16Mb and 23Mb, and your upload speed will be between 2Mb and 2Mb.

The minimum guaranteed speed you can expect from your BT Infinity will be 14Mb.

I am pleased that I have got an increased speed both down and up but at the additional cost of £10/month from what I was originally paying, that's what's taking the shine off things for me.

I will just say, probably doesn't make any difference but my old ADSL line (Up to 8Mbps) had been syncing at 8128 Kbps for many years, very stable connection.

Can you get the line stats too. and the DSL checker data. Those will show if the line is performing at its optimum.


If you cannot get anything faster then you may have a get out clause especially as they have provided an email- OR you could try negotiating a permanent discount.

The other bit is to figure our how far away the cabinet is in real world terms, just to check the attenuation figures once you have them make relative sense.

Have seen places when checking our checker where FTTC is only marginally faster than ADSL/ADSL2+

Our history with HH5 is not good. We are a good hike from our FTTC cabinet and BT would only sell us a 40/2 product rather than Infinity (and advising that our likely download would be in the 13 - 19 Mbps range on a self-install line). Using the HH5 router I was getting a sync speed of about 13Mb down. I replaced the HH5 with a Billion 8800NL and the download sync immediately went up to over 17Mb and we are now sync'd at 19Mb.

Upload is only just over 1Mbps whichever router is connected.

Maybe worth trying to beg, borrow or steal something instead of the HH5 to see if that is acting as a roadblock.

In reply to a post by MHC:

Can you get the line stats too. and the DSL checker data. Those will show if the line is performing at its optimum.

Line stats, from my HH5 are :-

Data Rate (I assume this is the line sync) :- 1225 / 11724
Maximum Data Rate:- 1225 / 11235
Noise Margin: 6.2 / 5.6
Line Attenuation: 18.0 / 37.1
Signal Attenuation: 18.0 / 30.8

DSL Checker is as follows:

FTTC Range A (Clean) 23.1 (High) 16.1 (low) 3.2 (Up High) 1.6 (Up Low) -- Available
FTTC Range B (Impacted) 17.3 (High) 7.6 (low) 3.1 (Up High) 0.8 (Up Low) -- Available

In reply to a post by MrSaffron:

The other bit is to figure our how far away the cabinet is in real world terms, just to check the attenuation figures once you have them make relative sense.

I am exactly one mile from the cabinet in the neighbouring village. This is line length, as I'm able to follow the phone ducts and the Post Office covers all the way from the pavement outside my house all the way to the cabinet.

In reply to a post by GonePostal:

Our history with HH5 is not good. We are a good hike from our FTTC cabinet and BT would only sell us a 40/2 product rather than Infinity (and advising that our likely download would be in the 13 - 19 Mbps range on a self-install line). Using the HH5 router I was getting a sync speed of about 13Mb down. I replaced the HH5 with a Billion 8800NL and the download sync immediately went up to over 17Mb and we are now sync'd at 19Mb.

Upload is only just over 1Mbps whichever router is connected.

Maybe worth trying to beg, borrow or steal something instead of the HH5 to see if that is acting as a roadblock.

I will try and grab access to my works VDSL router a TP-Link N600, which improved the works download speeds from the BT VDSL Modem and separate router combination.

I am exactly one mile from the cabinet in the neighbouring village. This is line length, as I'm able to follow the phone ducts and the Post Office covers all the way from the pavement outside my house all the way to the cabinet.

You still need to find the line attenuation. What you think you can see by walking along the road can be very different to reality.

In our location you can follow the ducts and poles along the pavement from the cabinets.

As my neighbour found when BT tried to reconnect the long disused phone line, her line went past the property and telegraph pole and was found to be connected at a pole 300 yards up the street, so it went past the house and back again to her home.

In reply to a post by AdrianPH:

You still need to find the line attenuation. What you think you can see by walking along the road can be very different to reality.

The post you reply to states the attenuation - but the OP was asked for line attenuation and distance to cab to see if they seemed to align. OP has provided both.

And the two do roughly align, so there may be a little to be gained by hardware/filter tweaking but not massive amounts

The cost equation all depends on what the extra speed lets you do that you could not before

I've just borrowed a TP-Link N600 VDSL router, installed it on my phone line and the sync went up by just over 2Mb, so it would seem that the BT HH5 isn't the best for long lines. I appreciate 2Mb may not seem like much of a jump, but for me, it was a welcomed sight.

Although this is still below the minimum sync levels guaranteed by BT from my first order. Once the 10 days training period is over, I shall contact them.

I am surprised they actually "guaranteed" the lower clean figure when the impacted ones were quite a bit lower. You might be in line for an interesting discussion.

Be aware the 10 day training is a myth, generally you are at around your likely stable sync after 48 hours, but it can go down or up at anytime for the years you keep the FTTC.

e.g. I ran at 20 Mbps for a few months, then banded at 15 Mbps for a while and then back to 20 Mbps again, with the odd trip to almost 24 Mbps now and then.

In reply to a post by MrSaffron:

Be aware the 10 day training is a myth, generally you are at around your likely stable sync after 48 hours, but it can go down or up at anytime for the years you keep the FTTC.

e.g. I ran at 20 Mbps for a few months, then banded at 15 Mbps for a while and then back to 20 Mbps again, with the odd trip to almost 24 Mbps now and then.

Thanks for the information, I decided to contact BT and they've now reduced my monthly fee, I'm now paying just £4 more than I was for 8Mb ADSL.

So, whilst I'm disappointed I'm not on a mega speed line, I do feel happier now that the price isn't much more than I was paying before.

A few things to think about that may improve your speed:

How far from where the line enters the property is the master? Does the cable run anywhere near to any electrical or electronic items? TV, Boiler, Fridge ...

How long is the master socket to modem cable? What type is is? Flat or decent twisted pair? Does the cable pass close to electrical or electronic times?

What else is located close to the modem?


IDEALLY, the internal wiring should be as short as possible to the master socket. A decent filtered face plate installed. Then a short Cat5e based RJ11 cable from master to modem. No TV, HiFi, Consumer Unit, Boiler, Fluorescent lights, FIsh Tank pump &c anywhere close to master or modem.

If that location is not convenient for your PCs &c you can run an Ethernet (Cat5e) cable from there to a small 4 or 8 port switch which then connects to the PCs.

Hi MHC,

In reply to a post by MHC:

A few things to think about that may improve your speed:

How far from where the line enters the property is the master? Does the cable run anywhere near to any electrical or electronic items? TV, Boiler, Fridge ...

The master socket is sat right over the hole where the cable enters the house, so there isn't any internal BT wiring.

In reply to a post by MHC:

How long is the master socket to modem cable? What type is is? Flat or decent twisted pair? Does the cable pass close to electrical or electronic times?

What else is located close to the modem?

IDEALLY, the internal wiring should be as short as possible to the master socket. A decent filtered face plate installed. Then a short Cat5e based RJ11 cable from master to modem. No TV, HiFi, Consumer Unit, Boiler, Fluorescent lights, FIsh Tank pump &c anywhere close to master or modem.

If that location is not convenient for your PCs &c you can run an Ethernet (Cat5e) cable from there to a small 4 or 8 port switch which then connects to the PCs.

The modem cable is about 3m long (10 feet), i don't recall it being any shorter and it's the flat type, to be honest I didn't know you could get any other type of cable like this, however, I've now ordered a good quality twisted pair cable and see how that goes.

Sadly my router is sat on top of my fridge freezer, due to being unable to place it anywhere else without adding much longer cables. It would simply get in the way if I just left it on the top next to the master socket. However, I shall attempt to move the router around the room though and see whether it makes any significant difference.

Thank you for taking the time to supply these tips, I greatly appreciate it, I will now attempt to try them all out over the next few days and will report back with any findings.

On a fridge/freezer can be quite bad. You will have two compressor and pumps plus other control circuitry there which can be a source of noise.

Try putting it near the master socket with the cable coiled up neatly and see what happens. If it does improve it - get yourself a separate modem and router set up. Wall mount the modem above the master and run Cat5e to the router which can sit on the fridge.

If you're connected to a Huawei cabinet then a modem with a Broadcom chipset will help as G.Inp will be enabled.

In reply to a post by BatBoy:

If you're connected to a Huawei cabinet then a modem with a Broadcom chipset will help as G.Inp will be enabled.

I hadn't got the first clue what you were on about until I did a internet search. Turns out I am on a Huawei cabinet, it was installed in September this year and went live at the end of October.

The new router I purchased does G.inp enabled as standard, so thankfully I go something correct there. Thank you for that information.


Also, does anyone know what the stats 'Max Rate' means on my new vdsl router, this wasn't on my old adsl one.

Basically it states :-

Current Rate (Kbps) 1273 up and 12976 down
Max Rate (Kbps) 1273 up and 15269 down (on my old BT HH5 this was 1225 up and 11236 down



I realise the current rate is what I'm synced at but what does the Max Rate mean?

If you look at the SNR margin it may well be above 6dB and if so, the MAX achievable is what the modem thinks it could achieve with a 6dB SNR. With 2.5Mbps difference, you may find that you do resync slightly higher in the near future. It is also possible, as I currently have, to have the Max Achievable lower than the actual sync.

As MHC says. Here's mine:-

Max: Upstream rate = 15947 Kbps, Downstream rate = 59808 Kbps
Bearer: 0, Upstream rate = 15142 Kbps, Downstream rate = 59997 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps

With:-
Down Up
SNR (dB): 5.9 6.4
Attn(dB): 19.7 0.0
Pwr(dBm): 13.6 7.4

Edited by RobertoS (Fri 27-Nov-15 16:46:46)