In reply to a post by cantoris:

Hi,

I'm using Virgin.net ADSL delivered over a SMPF connection.

My Netgear DGN2200 router often loses sync and disconnects when the phone rings. The past couple of days I've had problems getting it to come back without dropping again almost immediately although it does eventually stabilise - esp if I switch the router off for a bit. It's also been dropping at other times the past few days - eg mid-post here!

The occasional disconnect on phone ring has been going on for ages now (but only just now become really problematic) and continues despite a change in router and multiple attemps at changing microfilters - including buying brand new expensive ones rather than using spares that have come with routers over the years.

I would request the ISP to send an OR SFI engineer to check the line if turns out not to be a voice fault - seems like you have done all you can by changing routers, filters etc. and using the test socket. If it is a voice fault, and it can be fixed, then hopefully your broadband will stabilise

I had a similar problem last year, i.e. dsl dropping when the phone rang, although I had a quiet line, and an SFI engineer found the problem to be at the exchange after first checking at my test socket and then the cabinet.

I may be wrong, but it is my understanding, that like most filters, broadband filters have a cutoff point, thereby seperatong one set of frequencies within human hearing, from broadband data frequencies outside it. I fail to see how you could seperate one from the other while allowing full bandwidth. Sly seem top agree.
http://www.skyuser.co.uk/forum/view-filters.html
Also, see double filtering.

Edited by professor973 (Sat 15-Sep-12 17:14:05)

No I heard it with just a phone on the inner test socket.

The ADSL socket on a microfilter has no filtering applied to it. The modem itself contains a high pass filter to remove the voice frequencies.

If you look at the circuit diagrams here, you will see the RJ11 socket is unfiltered http://www.adslnation.com/support/filters.php

Can't you read? The sly Sky page you pin your hopes on even says:

In reference to www.skyuser.co.uk/forum/view-filters.html:

The one marked as modem is completely un filtered so when the router is connected to this it gets all the bandwidth including any voice signals - which the router simply ignores.

What's an "OR SFI" engineer and what do they do specifically?
Thanks!

Same applies to the A&B unfiltered adsl terminals on the back of a pressac faceplate.

In reply to a post by cantoris:

What's an "OR SFI" engineer and what do they do specifically?
Thanks!

Well the OR (Open Reach) SFI engineer, when he visited me, plugged the test equipment into the test socket and then made a phone call to my landline number from his mobile. After a few rings the equipment recorded a a very high error rate which was sufficient to drop the dsl connection. This very high error rate was found to be caused by a burst of noise, that was eventually tracked down somewhere in the exchange kit, that happened when the phone rang.

BTW. I was not billed for this visit since the fault was beyond the boundaries of my property and was entirely OR's responsibility.

OR = Openreach.
SFI - Serious Faults Investigation. Which in the past meant what it said. These days, pretty well anything that isn't obvious.