Having a very odd problem with my broadband.
If I make a phone call everything is fine.
If I receive an incoming phone call the router sometimes re-syncs the ADSL connection. This mainly seems to happen when my parents phone me. other incoming calls are normally fine (i.e. the ADSL stays up).

ADSL - Up to 8Mb with Zen internet.
Router -Draytek Vigor 2820
Router and phone both connected to the telephone master socket via a standard broadband filter (D-link).

Before I go and start taking things apart, is this likely to be the filter that's buggered or something else?

I'd try a filter, then try using the master socket.
Failing that it's a line issue

is the bell wire still attached in the main BT phone/connection socket
as it maybe an idea to disconnect the bell wire and then re-try the connection

also fitting a BT iPlate may help the connection …

Everything is already connected tot he master socket.
The master socket is a brand new one (Openreach) that incorporates the same technology as the iPlate and is the only socket in the house. It was installed by an Openreach engineer when I moved in so it's a brand new cable from the pole outside to the house and a brand new (well 1 year old) master socket.

I'll try another filter and see if that sorts it. Seems a bit odd that it's intermittent and only when I get a phone call from my parents.
Ah, the joys of technology.

within the BT socket are 3 wires attached to connections
if so then the bell wire is attached and enabled

removing the bell wire may help …

If you take the faceplate off you'll see another socket inside, which is separate from the main socket. If everything works fine in this socket (the master) then the problem is in your house, if the problem persists then there is most likely a fault on your line which BT will need to fix.

Well, I've put a new filter on so I'll see if that fixes it.

I know about the test socket but I doubt it'd do much good. It's used to isolate you from any internal wiring in the house. As there is no internal phone wiring in the house (except for a physically separate ntl phone line that's no longer connected) this really shouldn't be a problem.
Likewise, the master socket that the BT engineer fitted is a new model. It incorporates the same technology as the iPlate which removes the bell wire from the equation anyway (plus I watched him install the socket and I only saw him connect two wires).

If the new filter doesn't work then I'll do all the other tests (including using the test socket). I could really do without having to chase down an intermittent problem with BT. I really don't want to be charged for an engineer visit (I know they can't charge if the problem is at their end but if it's intermittent they may find nothing when they come out).

Fingers crossed.

BT's charging is a fcuking joke in general...

I agree 100%. When I moved into this house I had to get an engineer out to install the line.
I was miffed at being charged over £100 for some bloke to come out and flick a switch at the exchange.
In the end however the guy had to run brand new cable to the house from the pole on the other side of the street and replace the master socket because the old one had gone green inside
All told the Openreach guy was here for nearly the whole afternoon so I did get a lot mor work out of them than I was expecting.

They tried to charge a girl I work with's mother £150 when she got them out to sort out why her neighbours could hear her calls on their lines and vice versa

So it was a fault with their wiring.

That should be free.

Err, no. He paid for the installation of a new line. They don't do it for free.

Read that wrong. I though a bloke had been out to change the line to fix the fault. Read it too fast.

A wee update. Following some advice from someone on the Zen support page I rang my own number from my mobile while watching the router stats page. The TX & RX crc error count rocketed (500+ in a couple of seconds) as soon as the phone started ringing and the line dropped. This occurred regardless of whether or not the phone was even plugged into the line.

So, line fault at the exchange?

Sorry I've not re-read the rest of this thread, but that's one of three things:

1. The splitter at the exchange is faulty. This is quite unusual, but does happen.
2. A non-ohmic impedance on the line causing partial rectification when there's a current. This can be a faulty joint anywhere between the exchange and the router. Often it's a corroded connection in the street, but it could equally be your internal wiring.
3. You have an extension somewhere you've forgotten about. Usually it's a Sky box or similar which has been over looked.

Your wiring is the first thing to check. Unscrew the plate from the front of the phone socket to reveal the test socket behind, and plug your filter and router into that. There should be no cables going from that socket, and that's the BT demarcation point. Watch the router stats and make that phone call again. Filters are only 50p, so be sure to try two different ones.

Many older properties do not have the BT socket with the test plate, and may have star-wired extensions. If this is the case, then you can ask BT to provide a new style socket.

One thing you could do is ask your voice provider to run a line test with all apparatus disconnected, and another with just a phone. The automated tests you can run from the exchange are pretty comprehensive and should throw some light on the problem.