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[jamesbob]

After previous posts exploring a rise in CRC errors, error seconds, drops in SnR (falling below the usual 6) and rise in actual synchronisation resets..


.. I am now testing the same model at the master socket.

After almost 24 hours there have been no sync losses and no loss in SnR, no reported CRC errors. The bandwidth has increased from abovut 50/8 to 60/10 Mbs up/down.

This suggests the signal is being degraded in the home, this side of the BT master socket.

My question is - what are the common causes I need to look out for in a domestic environment?

The home is a very new build - cheap and low quality sadly. The telephone wiring was a star setup with the wires coming into the home being branched into about 4 rooms. Last year or before I cut the wire at the master socket so only one room was connected. That improved bandwidth by 5-10Mbs.

About two months ago the internet connection started being lost intermittently with good days and very bad days with about 10 disconnects a day. This is what caused me to investigate.

When the connection is poor, I notice the SnR is lower than 6, and that the spectrum as shown by the Fritzbox 7530 modem is not as full, particularly the downstream signal at the higher frequencies is attenuated.

I have just recently removed the dsl filter between the socket and modem and found it had no detrimental effect but no real improvement.

Also the issues happen throughout the night when no home electrical appliances are being used eg washing machine etc.

[Chrysalis]

Its basically a compromised signal, on DSL this will happen occasionally and is normal behaviour, you not going to get a totally error free DSL connection on a live public network.

The accepted remedy for it is basically error correction, or/and if using TCP retransmits.

[tubaman]

If the extension is not connected via a filtered faceplate then it will be creating a bridged tap and that could well cause a significant loss of speed.
If you are using dongle type filters then make sure there is one in each socket in use, but ideally you need a filtered faceplate at the master socket.

[Edinburgh_lad]

Lots of causes.

Master socket, or rather the filtered faceplate, to start with - the latest Openreach design (for a company having so much money to screw up that design so badly is unforgivable) means that it comes off easily and can be easily knocked off. I noticed that if the filtered faceplate not right in, this will cause FECs and also CRCs as you fiddle with it, and that's not the first master socket with such issues

- Hoover being too close to the router can result in my Internet dropping and I've noticed certain powerline plugs can have a detrimental effect on the quality of the connection, too.  For example, Devolo Mesh (rebranded Magic 2) caused lots of FECs and CRCs on my line than Magic 1. But this could be down to the way my wiring is.

- anything loose in terms of wiring, like lightning protection at the pole in our case resulted in SNR fluctuating and CRC errors. That's what Openreach told me, anyway, but whether they were telling me the truth is another matter.

This VDSL technology is very prone to issues, I've found.

[jamesbob]

If the extension is not connected via a filtered faceplate then it will be creating a bridged tap and that could well cause a significant loss of speed.
If you are using dongle type filters then make sure there is one in each socket in use, but ideally you need a filtered faceplate at the master socket.

Hi @tubaman I'm not an expert on faceplates and master sockets so I've attached a photo.

Is anyone able to tell me about it?

Just to be clear - connecting to the master socket like this results in an almost perfect connection (no dsl drops) but connecting in the bedroom socket is where the drops happen.

[tubaman]

A Master Socket 5C with a filtered faceplate looks like the one here - https://telecomgreen.co.uk/home-phone-repair/bt-openreach-new-nte5c-master-socket-guided-tour/ - with the filter effectively making the extensions invisible to the DSL signal.
With only a single extension if you connect to the extension it really shouldn't be making much difference so the fact that it does suggests an issue with the extension wiring. Can you show us the wiring behind the extension socket please?

[jamesbob]

With only a single extension if you connect to the extension it really shouldn't be making much difference so the fact that it does suggests an issue with the extension wiring. Can you show us the wiring behind the extension socket please?

Is this what you wanted to see? (image below)
The last time I took off the actual socket from the wall it was a bit of a mess behind and the left screw didn't really sit well with the hole it goes into so unless it will really help I'll avoid doing that again.

I can describe I think from memory what was behind there - the wire from outside obviously went to the back of the socket (the clasp?) and then after that went to something which split them into many wires, going back into the wall .. I assume re-appearing in the upstairs bedroom and downstairs sockets. The last time I did this I cut off the other connections leaving only the wires from one room connected -  the room with the modem. That was done by trial and error. I'm no expert but the wiring looked messy and unprofessional - not neat. But that might just be aesthetics. Previously my modem told me about "branching" but that stopped after the cuts.

Does this help or do you need more?

EDIT - I've found the old photos from my previous thread:

master socket: https://imgur.com/a/ulYVwAK
extension socket: https://imgur.com/a/hZESL7I

[Alex Atkin UK]

Its certainly possible that if the wires are all coiled around each other behind the master socket, any interference picked up by the extension is having some effect on the DSL signal, especially if that extension is picking up EFI from mains wiring or something.  I'd be adjusting the cabling behind the socket just to try to keep the incoming feed away from the extension wiring as much as possible.  Its a long shot, but you never know, interference can be a weird beast.

Personally I've used DECT phones for years to avoid needing any extensions connected at all.

[jamesbob]

hi @Alex - if I've physically cut the wires that connect all the rooms (except one) then there should be no interference from the in-house wiring?

I'm not using any phones at all - just one room with a modem attached - that's the only wiring that isn't cut at the master socket. Nothing else.

Let me know if I've misunderstood something.

[tubaman]

I can't see anything obvious wrong with the setup from a DSL perspective so the next thing I'd be trying is re-terminating the extension wiring at both ends in case there is a poor connection.

[jamesbob]

I can't see anything obvious wrong with the setup from a DSL perspective so the next thing I'd be trying is re-terminating the extension wiring at both ends in case there is a poor connection.

Thanks @tubaman, I appreciate you taking the time to advise.

Does re-termination mean taking the wires out at the master socket and the bedroom wall socket, cutting the ends off, and then re-connecting afresh into the fixtures (screw down in the bedroom, folding clip in the master socket) ?

[tubaman]

Thanks @tubaman, I appreciate you taking the time to advise.

Does re-termination mean taking the wires out at the master socket and the bedroom wall socket, cutting the ends off, and then re-connecting afresh into the fixtures (screw down in the bedroom, folding clip in the master socket) ?

Yes, precisely that.

[j0hn]

The screws that come with Master Socket 5c's are some of the worst I've used.
Look how rounded the screws are on your pic of the rear of the master socket. I bet you've only had that off the wall once.
You might get it off and on again once more but that would be it.

[Weaver]

james of you need a higher downstream or upstream or both SNRM, but with VDSL2 / FTTC it’s not something that even an ISP can easily control, if at all. You need the G.INP protocol which corrects errors very well and either is or is not available depending on the particular green FTTC cab that you’re connected to. We should be able to work out whether or not you have this.

One permanent cure, if you have deep pockets and reliability is important to you, is to get a second FTTC/VDSL2 line installed by the ISP Andrews and Arnold aa.net.uk (or other providers) and ‘bond’ the lines together. This gives you double speed in both directions because all the traffic gets split and sent down or up both links. This also gives amazing reliability because if one link loses sync or goes very bad then the traffic is all re-routed within seconds into the other link, so you don’t care about a modem’s loss of sync or other problem. In the case of Andrews and Arnold (AA), this traffic split even gives you double speed with all single downloads / uploads so you don’t have to have more transfers going on simultaneously in order to get the benefit. I seem to remember that with some other providers that’s not the case. Others who’re more knowledgeable will be able to tell you.