When it is sync'ed at 1425Kbps, does the phone have a dial tone? Similarly when at 2625.

If yes at 2625 and no at 1425, one leg of the pair is getting intermittent physical disconnects.

Edited by RobertoS (Tue 09-May-17 10:11:27)

That really looks like a noise issue kicking in and out. There are logs in the 2700 that show teh status just before a resync ...have a look at te SNR figures at that point.


<Settings> <Diagnostics> <DSL>

Can you do a screen shot of the Training History Table; the Mgn2 figure will be of interest.

Same thing happened last night. About 9 pm, the line dropped and resynced at 1512 kbps. This morning, it resynced at 2625 kbps. Time to contact my ISP, I think.

How do I read the logs on BT Firmware v5.29.117.6? If I go to <Broadband Line> <Diagnostics>, the only option is to run diagnostic tests.

Where do I find the Training History Table?

It is not really an ISP issue - if it happens every evening and then again in the morning there has to be a possible noise problem which the ISP has no control over.

I have a model, the same as yours, somewhere! but cannot find it at present - I think it is in use with a friend on a very long, long line.

Under settings, is there a Diagnostics tab? And if so, what is shown there? What further tabs are there?

You could also try using the Management and Diagnostic access:

http://gateway.2wire.net/mdc http://homeportal/mdc or 192.xxx.xxx.xxx/mdc (use the IP address yours is set to)


or maybe: http:/192.xxx.xxx.xxx/xslt?PAGE=C_5_3

You could work through all options changing the values in C_5_3 Using A-D for the first, 0-6 for the second and 0-6 for the third! It is almost certainly under the C_x_x area.

Edited by MHC (Wed 10-May-17 10:05:58)

192.xxx.xxx.xxx/mdc did it. I should have remembered that from when I unlocked it!

The training history is as follows:

https://www.dropbox.com/s/tvipgs8qxquac4v/dsl_diagno...

Looks as though your target margin is 15dB - maybe because of noise &c.

The ERR_SIGNAL_INTERRUPT indicates that the modem looses the signal quite suddenly and then has trouble retraining immediately shown by ERR_INCONSISTENT_SIGNAL. Is there something new in the house that creates electrical noise?


The morning resync is when the noise source disappears and the modem realises there is extra speed available - in each of the three cases there is 5dB extra which it uses to increase te speed from 1400 to 2500.

A modem that auto-resyncs when noise drops? AIUI we don't have rate adaptation at the moment either.

I phoned Zen last night.They surmise that an appliance is injecting a noise spike in the evening, followed by continuing line noise that causes the modem to resync at the lower rate. They said it was curious that it resyncs in the morning, since the modem wouldn't resync just because the noise had gone away. That suggests there's another spike when the appliance switches off. Since the noise has then gone away, the modem resyncs at the higher rate.

I've been scratching my head trying to think what comes on about 9 pm at night, stays on all night, then switches off in the morning. I can't think of anything in the house that fits that description. I wonder if the problem is caused by the lamps in the street outside. The line drops seem to correspond to the times that the street lamps go on and off. We have overhead telephone cables. The council have recently replaced some of the sodium lamps with LED lamps.

Zen forced interleaving on, which resulted in the modem resyncing at 2777 kbps. The line didn't drop last night. I'll continue to monitor.

LED street lights are pulse modulated, their power supplies generate a lot of RFI as many radio amateurs will confirm, swamping HF frequencies with even more noise. Therefore they will affect xDSL.