Unresolved support ticket open for more than six months - is this a record?

[#1]

Well, two BT engineers arrived today and completed a number of checks, including checking for interference using a portable radio tuned to 612Khz AM (they didn't find anything significant). They also checked the red/black phone wires in the roof and suggested that this was actually an old-style phone cable that didn't need replacing; however, they did fit an RF filter instead of the snap-on connectors - see attached photo. The master socket's filtered faceplate (an ADSL Nation XTE-2005) was also replaced by the engineers i.e. it is now a standard BT filtered faceplate.
The engineers also checked the line connections at the local exchange but couldn't find any faults. The line from the exchange to the Primary Connection Point (about a quarter of a mile from my house) was also changed (swapped?), so that just leaves the line from the PCP to my house that could potentially be changed in future.
The engineers' tests showed that the line can synch at around 6000kbps, but the actual throughput seemed to be restricted to around 2000kbps (which ties in with my experience i.e. throughput is generally a fraction of the synch rate). They couldn't offer any explanation other than the ISP (i.e PlusNet) may be restricting throughput - I explained that PN had already confirmed that traffic management was not a factor, so it seems we're all none the wiser as to what's causing the problem...
As the engineers ran out of time (limited to two hours per visit) they were unable to consider replacing any cabling on the D-side. I've suggested to PN support that it must now be time to pass this problem on to BT's Complex Faults Team, so I'll let you know what happens next.
I've copied the latest BT speed test results (as at 13:46) below:-
Test1 comprises of Best Effort Test: -provides background information.
Your DSL connection rate: 1344 kbps(DOWN-STREAM), 448 kbps(UP-STREAM)
IP profile for your line is - 1750 kbps
Actual IP throughput achieved during the test was - 1043 kbps
(SNR margin is 6Db and line attenuation is 22Db)

[#2]

Someone is talking rubbish.
Your synch rate is 1344kbps so I totally fail to understand how the engineers tests can show that your line can support 6000kbps unless your router, filter, internal wiring, connection to the master socket are badly at fault.
Did they do a test sync with their modem and did it give much better speeds

[#3]

Only BT have the ability to profile / throttle the sync speed.
What sync speeds did the engineer get from your master socket?

[#4]

Yes, I thought it sounded a load of hogwash! The engineer said he had synched at about 6000kbps and this was using the new filtered faceplate that he had installed earlier today. But he couldn't get throughput higher than about 2000kbps.
The only difference, as far as I can see is that BT connected directly to their broadband service i.e. bypassing the PN service. And, of course, I'm using a different router (but I'm happy that this is not causing the problem as I've tried swapping this with two different routers in the past and they've had similar problems).

[#5]

The realm that the engineer uses should make absolutely no different to the sync speed.
I'm curious to find out how he got the faster sync speed, if he did at all!

[#6]

Out of interest can you connect only your router to the faceplate with nothing elso connected exactly as the engineer did.
Do you have a different cable from the faceplate to the router that you can try.

[#7]

Quote from: Jameseh

I'm curious to find out how he got the faster sync speed, if he did at all!

Me too! But, to be fair, previous engineers have also obtained a 6000kbps synch speed and this has been maintained for a few hours after they left i.e the normal pattern would be for the synch rate to drop away after a few hours. BT apparently don't normally test throughput (if you believe this engineer) as they are just required to check the synch rate i.e. the BT view is allegedly that throughput is the ISP's responsibility.
By way of an example, the previous BT engineer visited on 22nd December and the synch rate was maintained at over 6000kbps from about 1pm to late evening when it dropped to just under 4000kbps; synch rate then dropped to around 1200kbps the following day. Actual download speeds (using Mybroadbandspeed), however, were no higher than 700kbps throughout this period (even when synch rate was 6000kbps). BT's speed tester also confirmed this low IP throughput.
And just for clarification, in case anyone is wondering - BT engineers are not permitted to test customer's pc equipment, routers etc i.e. they only use their own laptops and modems when conducting performance tests.
I've also tried changing the ADSL and LAN cables on several occasions - current set-up is a very short ADSL cable (50cm long) and a short LAN cable (1m long). And I just have a BT corded phone plugged into the faceplate - I previously had a Panasonic DECT phone, but removed that a couple of weeks ago to try to eliminate any potential sources of interference. I can't think of anything else I can reasonably be expected to change.

[#8]

Ok - What are your line stats like when testing from the test socket?

[#9]

Exactly the same i.e. because I'm using a filtered faceplate on the master socket, this is effectively the same as using one of those "dangly" micro-filters plugged directly into the test socket. I've attached a photo of the new filtered faceplate that BT installed this morning.
And I have tried different types of micro-filters in the past as well i.e. before I tried the ADSLNation XTE-2005 faceplate (which also plugged directly into the test socket). And before anyone asks, I know that you have to remove the bottom half of the NTE5 faceplate to access the test socket.

[#10]

Thanks - To remove any possibility of the faceplate being faulty (which can happen), can you try removing the faceplate and using the test socket.
Appreciate that it is effectively the same thing, but there's an outside chance that the faceplate may not be helping matters.

[#11]

OK, I removed the filtered faceplate (at 16:13) and plugged an ADSLNation XF-1e microfilter directly into the test socket - see attached photo. You can also see the back of the BT filtered faceplate i.e. you can see that the plug will connect directly into the test socket as well. My router is now reporting a synch rate of 1472kbps with SNR margin of 6Db and line attenuation of 22Db.
Just to confirm, though, the BT engineer did his tests via the filtered faceplate that he installed earlier i.e. he didn't use a separate microfilter plugged into the test socket.

[#12]

You've got the phone plugged in as well there. Does it make any difference if only the router is plugged in?

[#13]

Quote from: Catweazle

SNR margin is 6Db and line attenuation is 22Db

With that you should get a solid 8meg max speed connection!
So 2meg is bizarre.
Have you run the DMT tool and posted the tone graph here for comment?
Also, can you take off the master socket backing plate and show how that multicore incoming cable is connected - post a close-up photo.

[#14]

Quote from: jelv

You've got the phone plugged in as well there. Does it make any difference if only the router is plugged in?

Well, I unplugged the phone and it made no apparent difference - I've tried this before on several occasions e.g. when I was testing with no phone attached, or when swapping my DECT phone with my BT corded phone. The BT engineers always test with the phone unplugged, so it's a good suggestion, but I don't think it makes any difference. BT also changed the master socket last year and that didn't make the slightest difference either.

Quote from: HPsauce

[Have you run the DMT tool and posted the tone graph here for comment?

I have a Draytek 2600G router, so I don't think I can use DMT - correct me if I'm wrong, please. I'll try to post a more detailed pic of the master socket later.

[#15]

Quote from: Catweazle

I have a Draytek 2600G router,

Without rereading the whole thread I recall you tested with a Netgear DG834 variant at some stage. Which one exactly?
If it was me I'd put that back into use and flash it with DGTeam firmware for better control and more detailed diagnostics.