Connection unreliable and slow

[#1]

Up until about a month or so ago my broadband connection was generally stable and sync'd at 4Mb+ (often around 5.5Mb).
Now I get frequent disconnects and periods when the negotiation will hang at "LCN allowed to come up" or some such message.  When I do connect the negotiated speed tends to be well down (2.4Mb max, frequently lower than 2Mb).
I'm using a netgear router and nothing in my setup has changed.  Any suggestions on what might be wrong and how I should proceed to get back to my previous quality of service?

[#2]

Hi there,
I've just run a quick test on your connection and it's not showing anything obviously untoward.  the sync speed definitely looks on the low side, but there's nothing obvious that's causing it.
Can you try:
- Replacing your filters
- Making sure that your router is connected directly into the master socket via a filter
- Use the test socket if possible
- Try using a different router if possible
- Making sure that all of your used telephone sockets are filtered
Let me know how you get on and I can run another test.  If the situation is still the same, we can raise a fault to BT for you, because your connection rate is below what they call the fault threshold rate.

[#3]

Hi James,
Thanks for the prompt reply.
My router is connected to a BT-installed socket with DSL and phone ports.  All the filtering takes place in this socket and I do not use microfilters elsewhere.  I think this is the master socket although there is an external box where the phone line emerges from the ground.
I've tried unplugging all my telephones and that seems to make no difference.  I'll try another router tonight. 
I'm not sure where I would find the test socket.
Len

[#4]

I have similar messages when using my Netgear router - I think you mean LCP, rather than LCN.
Don’t want to get you more depressed but my connection problems started 3 weeks ago today and I’m now unable to use my broadband!
The checks requested might help you, but buying new filters, a ‘factory-reset’ on my Netgear router, and purchasing a new router, etc. etc. and countless phone calls and updates to my support record has yet to solve things.
Hope you have more success.

[#5]

Hi Len,
Are you saying that your master socket has a faceplate with phone and DSL ports?  If so, don't worry about the test socket or filters.
Let me know how you get on with the different router.

[#6]

Martin - I'll give you  a call shortly.

[#7]

Quote from: Jameseh

Hi Len, Are you saying that your master socket has a faceplate with phone and DSL ports?  If so, don't worry about the test socket or filters. Let me know how you get on with the different router.

Yup.  It was installed by a BT engineer in the bad old days of 512k ADSL and before customer-setup was available
I'll try another (netgear) router this evening.  I've also located a standalone ADSL modem.  I'll give that a try if I can
find the drivers for it.
Martin, yes - LCP.  Thats always a problem when you do this sort of thing away from the machine in question!  And you have managed to depress me

[#8]

Ahhh, well.
As is always the way, negotiated speed tonight is back up to 4.7Mb.  I'll try the other router next time it goes back down and post the results here.

[#9]

Hi.
Well, got home tonight and the downstream speed was reported as 244k by the router.
Rebooted router and it went up to 1200k
Connected a new router and it went up to 2880k
Reconnected the original router and it went up to 4416k
So, it doesn't look as though there is anything seriously wrong with the router.  It looks as if the next player should be BT
Thanks