In reply to a post by WWWombat:

What components exist on the backplate of the master?

That is, between the screw-connectors for the incoming twisted pair and the output pins of the test socket on the backplate.

If lightning could affect the SSFP, could it not also/instead affect the backplate?

Actually, thining back to the engineer's visit, he did replace the whole shebang rather than waste time testing each part of the master socket's build-up.

I'm not sure what components exist on the backplate but just for reference, the connections are IDC rather than screwed.


I may have a photo somewhere from when my whole master socket was replaced a couple of years ago.
I'll post a link if I can find it.

That's what's making me think it is more of a physical cable/connection problem rather than noise.

I've had three faceplate / backbox changes. Also at least two of the OR engineers have attached their test unit directly at the old GPO pattress where my underground cables come into the house (and are gel-crimp-connected to the cable that goes to the master socket) so it's not that.

Come to think of it, the complete fail that I mentioned was a day or so after the thunderstorms. Maybe a neighbour's VDSL modem is to blame ...

O.K. So more & more potential sources of the problem are being eliminated bit by bit.

It may seem quite extreme, but to completely eliminate anything interference-wise being generated in your home you could try this:-


Make up an adapter with a suitably sized plug to fit the modem's power socket & bare wires at the other end.

Set up a laptop with a fixed Network Controller IP address within the same range as the modem.
(I have previously done this using 192.168.1.1 for the laptop's fixed IP address)

Turn off all your mains power at the consumer unit.

Connect the laptop's NIC to the HG612's LAN2 port via a good quality ethernet cable.

Connect the power adapter cable to a 12v battery, ensuring correct polarity.

Connect the HG612's DSL cable to the main test socket using an ADSL microfilter.

When the DSL light is steady on the HG612, access the HG612 from the laptop via a telnet session, using 'telnet 192.168.1.1' (without the quotes) in a Windows CMD window.

Enter 'admin' for Login & 'admin' for password (without the quotes).

Enter 'sh' to get into BusyBox (no quotes)

Enter 'xdslcmd info --stats' (without the quotes) & wait for the results

Enter 'xdslcmd info pbParams' (without the quotes) & wait for the results.


Copy all the telnet output data & post it in this forum thread or paste it to a text file & upload it somewhere we can access it.



If the 'interference' was actually being generated from within your house, you may not see increased sync speeds in the telnet output as DLM may need time to react, but you should be able to see significantly increased US (& maybe DS) SNRM values.



If there is indeed a noticeable improvement, whilst still powering the HG612 from a battery, you could try tuning the power back on, circuit by circuit until the 'offending' circuit is identified.

You would need to keep re-running the telnet commands to check for any changes as each mains circuit is switched back on again.


If an offending circuit is identified, try switching off/unplugging ALL appliances on that circuit & then switch them back on one at a time, re-checking the telnet output until the offending appliance is identified.


If there is a deterioration only when the modem's usual power adapter is plugged in, that could be the source of your problems.




If nothing improves at all with ALL the mains power off, at least something else will have been eliminated & it might be useful to explain what you did to your ISP and/or the next visiting engineer.


Of course, if it really is an interference problem, the source could be somewhere in a neighbour's house or even a defective street light, arcing underground mains cable etc. etc. etc.


All this does seem to be quite a rigmarole, but it's possibly the only way you will be able to convince anyone that you are not causing the problem yourself.


Good luck & please keep us posted.

The OP does mention it is affecting several other houses close by.

A physical connection issue would also manifest itself on the downstream, which I hope you will agree, looks reasonable.

Laptop - no problem; that's how I flashed the modem. I think I have a 12v motorbike battery somewhere, but It might be easier to try with all upstairs MCB's off, and again with all downstairs MCB's off and power the modem via an extension lead plugged in upstairs.

In reply to a post by MHC:

The OP does mention it is affecting several other houses close by.

Yes, but if they are ADSL users (we don't know one way or the other as it wasn't specifically mentioned), they probably wouln't notice anyway as the frequencies in question are not used for ADSL.

In reply to a post by Reentrant:

but It might be easier to try with all upstairs MCB's off, and again with all downstairs MCB's off and power the modem via an extension lead plugged in upstairs.

It might be worth a try doing it that way, unless it's down to mains borne interference.

My hunch is still related to a possibly defective cable from the last access point or a dodgy connection joint.

Amateur radio nearby?

In reply to a post by MrSaffron:

Amateur radio nearby?

Not that I'm aware of; no new obvious aerials have appeared recently. All phone cables round here are underground - would that make them less susceptible to RFI than pole-strung?

I can't find a suitable 12v supply so I've ordered a car inverter. It will be a few days before I can get the telnet stats.