Low Sync speeds recently

I have had ADSL installed when we moved into the house May 07 and it has been reliable since then syncing with BT @ about 7000kbps.

About 2 weeks ago I got back from a weeks holiday to find my sync at roughly 1000kbps with an IP Profile of 135kbps (ouch)

I figured either BT have been doing maintenance on the exchange or the router flipped out so I reset the router which reconnected sync at 4000kbps. After a few days the IP Profile is back up to match the 4meg sync.

10 days later, the router still won't sync back at 7mbs like it has for > 2 years

I took the cover of the BT Master socket to try the test socket out, and there isn't a test socket! I then traced the line from the dining room to the porch where I find the line running into a DACS box. I thought ADSL was incompatible with DACS so I can only assume its redundant.

Any suggestions on what could be the issue, and wtf is up with the DACS box?

In case anyone isn't sure that I really was synching at 7megs - I frequently dl from newsgroups where I get speeds of 700kbps, and in the couple of days before I left for my hols I was flagged twice as a high user by Entanet. Im also a little over 1km from exchange as crow flies.

Could you post your stats? They give a good idea of your line state.

See http://www.dslzoneuk.net/adsl_line_stats.php

DSL Status: Up
DSL Modulation Mode: GDMT
DSL Path Mode: INTERLEAVED
Downstream Rate: 4992 Kbps
Upstream Rate: 448 Kbps
Downstream Margin: 2147483646 db
Upstream Margin: 26 db
Downstream Line Attenuation: 40
Upstream Line Attenuation: 26
Downstream Transmit Power: 0
Upstream Transmit Power: 0


PVC Connection

Encapsulation: RFC 2364 PPPoA
Multiplexing: VC
QoS: UBR
PCR Rate: 0
SCR Rate: 0
Autodetect: Disable
VPI: 0
VCI: 38
Enable: Yes
PVC Status: Applied

Item Value
ADSL Line Type GDMT
ADSL Line CodingADSL Line Coding INTERLEAVED
Line Attenuation (Down):40 (Up):26
Noise Margin (Down):2147483646 (Up):26
Total Output Power (Down):0 (Up):0
Current State DownStr: 4992(K) UpStr: 448(K)
undefined UP
FEC(FAST) (Near):0 (Far):0
FEC(INTERL) (Near):68 (Far):254836619
CRC(FAST) (Near):0 (Far):0
undefined (Near):1 (Far):236
HEC(FAST) (Near):0 (Far):0
HEC(FAST) (Near):68 (Far):0
Showtime last(sec) 470421
ADSL FW Version 0.54
ADSL Board Type Annex A

hmmm just been checking those stats i would dial 17070 free from your landline you want to do a quiet line test you shoull hear nothing but a very very faint "iss", if you do hear crackling etc you problem is a noisey line mate, i think its option 1 or maybe 2 can't remember but she will say this circuit is defined as (your number) then she will say welcome to BT line test facilities please press 1 for quiet line test or 2 for ring back test, might be the other way round not sure was while ago since i worked for BT,

You've definitely got a problem with your downstream noise margin. The figure of 2147483646 db indicates that the noise margin has probably gone into a negative figure. This is often seen on routers such as Netgears as they're generally pretty good at hanging onto a sync where other routers may just give up.

Do the quiet line test, I'd be surprised if you don't hear some noise.

2147483646 - 2147483648 = -2 dB

John.

I knew someone could do the maths

Its been a while, so I figured Id get back to let everyone know what happened.

I tried the quiet line test but as I have cordless phones was unable to tell if that was the issue.

I eventually took the plunge and registered a fault with BT knowing that if I was wrong I would end up having to pay for the callout.

Last week we had a call the day before the engineer was due to say he would check out the exchange first and only come out to the house if he couldn't fix the problem there. The next day we had a call from the engineer to say the problem was fixed at the exchange.

After checking the DSL stats I now get a sync speed of 8mbps which is even better than it was before and I didn't have to pay for a callout which is a darn good result. latency is lower too.

The only thing I am a little disappointed with is because the engineer didn't come out to the house I couldn't satisfy my curiosity over the apparently redundant DACS box on the line.

Thanks to everyone for the help.