There are literally thousands of ports marked as faulty for investigation across the country. It would probably take a month to go through them all if you diverted every single openreach engineer to it. As it is there are probably less than 50 across the country at any one time dealing with anything from a single slow speed fault to loss of headend affecting thousands. The old FTTC network is very poorly respected and some of the cabinets have been abused by people that dont know what they are doing.

If an NGA engineer has been to look at your port they will check the attainable rate. If it is poor they will try to rectify it but it maybe that is best available . Could be cross talk on a highly loaded cabinet or damaged ties or a card fault.
If its intermittent and tested ok then the incident would be closed.
I doubt that it is a wide scale problem across the cabinet otherwise it would have been escalated. Unfortunately you can only raise the issue again with your SP and and perhaps escalate it yourself to directors level within openreach if you feel it warrants that.

The point is that I was synching at (and stable at) around 60Mbps until the first engineer changed the ports and it dropped to belwo 50Mbps, and since then none of the engineers have been unable to get it back up to anywhere near the 60Mbps I had.

I have been getting 58 - 60Mbps for the last 4 years without issue. The issue started when the line dropped one weekend early in December.

The only thing that changed around that time was that Openreach subcontractors pulled fibre through the ducts in the street. But, every engineer has tested the line, with one even tracing it through the street access manholes. They have all confirmed there is no fault with the line between the cabinet and my house.

In reply to a post by Fastman3:

just so we clear what happens between the exchange and dslam is irrelevant -- , Services are offered only up to max of 80 m/bps - that actually tranmit out at 76 (at a max no one will ever get 80) - based on about 500m i would expected you about some where between 50 - 60 meg at best efforts

@Fastman that's not true. I sync at 80/20 Mbps in my TalkTalk router settings and I also get 80/20 in speed tests. Not absolutely every single time but most of the time I get speed tests of 80 Mbps download and 20 Mbps upload with various speed test sites.

Here's proof. https://i.imgur.com/6XC1WI7.jpg
https://i.speedof.me/201205000112-233
https://i.imgur.com/h01UK8f.jpg
https://i.imgur.com/k8Lmgoh.jpg

Some of them, not exactly 80 Mbps but all above the 76 Mbps speed test that you say. With one of them 81 Mbps. I'm on a cabinet that's 320 meters approximately away. People much closer will pretty much guarantee sync speeds of 80 Mbps and 20 Mbps upload barring crosstalk.

Even though speeds can be offered at max 80 Mbps cap. The cabinet measure speed can go higher than that. For example Bonded FTTC can give you up to 280 Mbps with Cerberus but very expensive at £300 a month. The checker will give variable speed estimates based on cabinet distance on bonded FTTC packages.

Do you know what happen when your line dropped and what was done to fix it?
Exactly what was faulty? Did any of your neighbours have problems at the same time?

Sounds like your line was cut and is now impacted due to a splice.

In reply to a post by Eeeps:

Sounds like your line was cut and is now impacted due to a splice.

Am I the only one confused by this comment?

In reply to a post by dect:

In reply to a post by Eeeps:

Sounds like your line was cut and is now impacted due to a splice.

Am I the only one confused by this comment?

Could they mean that the cable has been cut and spliced back together? It's a possibility i guess, but any OR test surely would find a faulty re-join on the line.

In reply to a post by Whitehall11:

Could they mean that the cable has been cut and spliced back together? It's a possibility i guess, but any OR test surely would find a faulty re-join on the line.

I've never heard of a copper or aluminium cable being spliced, it would normally be crimped thats why I was confused by the comment.

In reply to a post by Eeeps:

Do you know what happen when your line dropped and what was done to fix it?
Exactly what was faulty? Did any of your neighbours have problems at the same time?

Sounds like your line was cut and is now impacted due to a splice.

I'm also confused by your post. My line was dropping formerly on EO Line on ADSL. It would quickly reconnect within 1-2 minutes but my connection wouldn't maintain stability with a 3dB or 6dB SNR. When I contacted my ISP to manually increase the SNR to 9dB only then my connection was stable but at reduced speeds such as 12Mbps.

My line was not cut. There were no physical damages to the cable. But I believe due to the long length and noise on the line the connection would never remain stable for more than 1-4 days. Neighbours in my case didn't have problems at the same time, but they suffered from the same disconnection problems as soon as SNR dropped to 0dB connection cuts off.

My EO Line FTTC cabinet got upgraded in October 2019 and this month is exactly 1 year since I now have FTTC. My connection problem spontaneously got resolved from the FTTC switch and I now have 80/20 Mbps rock solid last 12 months. It is a 24 month contract with TalkTalk and I am no longer experiencing these problems.

My connection on ADSL was always having issues and Openreach engineers were never able to fix it. Even after my EO Line got upgraded to FTTC nearly 2 years ago my ADSL was still suffering. It was only after I had switched to FTTC following my end of the ADSL contract with Plusnet did my problem get resolved.

I know that till this day people in my area (Bishopsgate exchange) who are on ADSL will still have problems, but switching to FTTC immediately rectifies the problem. Many people here on these forums and on Youtube have had the same experiences. Generally speaking FTTC with shorter copper cable length to the cabinet reduces risk of noise and that should normally resolve the problem automatically. But OP is obviously unlucky that his length is 550 meters long, I'm guessing there is some random noise problems on his lines that is causing his drop-outs.

In reply to a post by BLaZiNgSPEED:

I'm guessing there is some random noise problems on his lines that is causing his drop-outs.

There is no random noise. There was only ever the one drop out which happened on a Sunday afternoon. The next day there were drops and re-syncing at 1Mbps.

I initially reported the problem as a disconnect over the two days.

The slow speed is a result of the Openreach engineer changing my ports. I was getting speeds of around 60Mpbs stable for around 4 years previously.