Recent line issues - advice greatly appreciated

[PTG]

Hi Everyone,

Back in November 2020 I upgraded from ADSL to Fibre FTTC (36Mpbs Max). Previously on ADSL I had 11.85Mbps down speeds and approx 1Mbp up speeds. Moving to Fibre I have had 31.85 down speeds and around 5Mbps up speeds until 2 weeks ago when I've had nothing but issues. 

Whenever I attempt to use the landline telephone to make a call or if a call comes in, the EE Smart Hub reboots. If the telephone is still in use when the router tries to resync, the upstream can drop as low as 459Kbps. If I reboot after the telephone line is free, the upstream sync goes back higher. Due to the number of disconnections recently and with DLM no doubt, I'm now down from 31.85Mpbs to 20.0Mbps and the upstream has gone from 5.06Mpbs to 2.08Mbps. I have already connected the router into the test socket within the Master Socket which bypasses the interior wiring. I've also replaced the filter, the cable from the router to the filter, the router itself (have an old BT Openreach FTTC white modem), different landline phones (corded and cordless) to rule out my equipment.

Initially reporting to EE I was told on the landline side I had a fault at the exchange - probably a faulty line card and would be fixed without an engineer appointment the next day. This never happened and when I called back 2 days later nobody could find a fault on the line and the job was 'rejected' on their end - whatever that means.

The first Openreach engineer came out on Monday and replaced the entire Master Socket NTE 5A with a new 5C type. My previous Master socket was fitted way back 2011. He did line checks and couldn't find an issue and insisted the fault was down to the Master socket due to 'degradation over time'. Annoyingly, when he was here and after fitting the new socket, all appeared well initially. I used the telephone repeatedly when he was onsite and dialled out to my mobile for up to 2 minutes and used my mobile to call the landline. The connection didn't drop and the upstream held at 4.87Mbps. The downstream had already dropped by this point to 27.4Mbps but all appeared fine. I thanked him and off he went. Yet less than 2 hours later, the telephone rang and the router disconnected again!

I should add that way back in 2017, I had a similar issue on ADSL and it turned out that I had an E-Side fault. However, on FTTC, can you still have E-Side faults as it's now Fibre to the green cabinet? I have a 'more senior' Openreach engineer booked to visit this Monday, but don't want to be fobbed off. Surely I have a fault on the line somewhere. Any advice would be most welcome! Thanks.

Here's a post of some logs over the last few days and a photo from the BT Wholesale checker website (I've removed my number and exchange for privacy etc).

17/5/21

Data rate:4.64 Mbps / 22.40 Mbps
Maximum data rate:4.66 Mbps / 36.85 Mbps
Noise margin (up/down):6.1 / 8.7
Line attenuation (up/down):36.1 / 23.7
Signal attenuation (up/down):23.6 / 21.0

Data rate:1.59 Mbps / 22.40 Mbps
Maximum data rate:1.59 Mbps / 36.70 Mbps
Noise margin (up/down):14.4 / 9.4
Line attenuation (up/down):34.6 / 23.8
Signal attenuation (up/down):23.1 / 21.0

18/5/21

Data rate:459.00 Kbps / 22.40 Mbps
Maximum data rate:440.15 Kbps / 29.94 Mbps
Noise margin (up/down):5.0 / 6.6
Line attenuation (up/down):29.4 / 24.0
Signal attenuation (up/down):4.4 / 21.2

Data rate:4.34 Mbps / 22.40 Mbps
Maximum data rate:4.34 Mbps / 36.51 Mbps
Noise margin (up/down):6.0 / 8.6
Line attenuation (up/down):36.1 / 23.8
Signal attenuation (up/down):23.7 / 21.0

19/5/21

Data rate:2.53 Mbps / 22.40 Mbps
Maximum data rate:2.54 Mbps / 35.64 Mbps
Noise margin (up/down):7.1 / 8.9
Line attenuation (up/down):35.8 / 23.9
Signal attenuation (up/down):23.5 / 21.1

20/5/21

Data rate:2.49 Mbps / 20.00 Mbps
Maximum data rate:865.80 Kbps / 34.65 Mbps
Noise margin (up/down):0.6 / 9.3
Line attenuation (up/down):34.6 / 24.0
Signal attenuation (up/down):23.2 / 21.2

** TONIGHT (After a phone call!) **

Data rate:459.00 Kbps / 20.00 Mbps
Maximum data rate:470.63 Kbps / 36.03 Mbps
Noise margin (up/down):12.4 / 11.3
Line attenuation (up/down):28.4 / 23.9
Signal attenuation (up/down):4.3 / 21.1

[Mustrum]

@PTG your pic will appear after a mod has approved it.

Clearly something not quite right, but if you can't replicate the fault when the eng is on site, they don't have much options, other than move on. You have to be patient, hopefully Mondays eng will find more.

That kind of fault tends to be either the filter at your end or the line card in the exchange, but could be elsewhere.

[XRaySpeX]

Locate the hidden test socket that is revealed when you remove the bottom half of the split faceplate (2 screws or press tabs) of your master socket. Only do this if you have a split faceplate. Do you have any extension sockets in the home even if unused? Are there any wires connected to back of faceplate of master socket?

Try the BT Quiet Line Test (QLT), dial 17070 Opt 2, preferably with a corded phone, in the test socket with the router disconnected. If there is any noise, report it to your landline provider as a voice fault (don't mention Broadband). Often sorting out voice faults will fix the Broadband as well.

Reboot the router & plug it into the test socket. Post the full router stats & System Uptime when plugged into test socket.

Is the issue any better?