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Query: Sync speeds and Line Attenuation/SNR

N/A

Query: Sync speeds and Line Attenuation/SNR

Hi,

I was wondering what sort of sync speeds should be seen with different line attenuations and noise margins?

Currently my line stats are as follows:

DSL Status
Connection Status Connected
Upstream Rate (Kbps) 448
Downstream Rate (Kbps) 3040
US Margin 22
DS Margin 12
Modulation GDMT
LOS Errors 0
DS Line Attenuation 24
US Line Attenuation 21
Path Mode Interleaved

Is this sync speed I'm seeing in-line with what I can expect given my line stats? I ask this because according to BT I should be able to acheive speeds of at least 6.5Mbps and I live about 1km from the exchange. My line was activated within the last few days so I understand I am still within the 10day settling down period.
8 REPLIES
N/A

Query: Sync speeds and Line Attenuation/SNR

Your SNR margin is set quite high at 12dB (this will have a negative effect on your sync speed).

Also you have interleaving enabled.

Do you know if you are on the LLU platform (Tiscali) ? These stats look very Tiscali - the default (and only profile) is 12dB SnR and interleaving on LLU. Plusnet are looking to get more profiles added so people with stable lines can sync faster.

The BT checker will return results that roughly correlate to speeds you would get on a BT Wholesale product.
shellsong
Grafter
Posts: 2,191
Registered: 03-08-2007

Query: Sync speeds and Line Attenuation/SNR

The upstream rate of 448Kbps suggests MaxDSL
N/A

Query: Sync speeds and Line Attenuation/SNR

missed that Shockedops: thanks..

In that case, the fact you have interleaving enabled and a target SnR value of 12dB suggests your line was unstable when max went live on it. It's usually people's extension wiring that's the issue here...
N/A

Query: Sync speeds and Line Attenuation/SNR

extension wiring, yes that could well be an issue. There is a lot of it in the house because we have phones in several rooms and I'm not even sure whether the socket the modem is plugged into is the master or whether the socket downstairs is the master.

Think I wil have a look into getting some DECT phones and then disconnect the extensions.

Just by unplugging some of the extra phones I managed to get the line attenuation down to 22dB
Slipperymack
Grafter
Posts: 98
Registered: 05-08-2007

Query: Sync speeds and Line Attenuation/SNR

Brainsurge -re: DECT phones.

I have problemss with my DECT phone (BT synergy) in that on some occasions my line looses sync when the phone is used.
N/A

Query: Sync speeds and Line Attenuation/SNR

I don't understand how or why that would happen. I thought a DECT phone system consisted of a base station connected to the phone line like an ordinary phone and then the remote handsets connected to the base station wirelessly? So I would have thought that as long as the base station is connected to the phone line via a micro filter then all should work fine?
Slipperymack
Grafter
Posts: 98
Registered: 05-08-2007

Query: Sync speeds and Line Attenuation/SNR

I personally have tried BT, Phillips and Panasonic DECT phones with a base unit downstairs and a further unit and phone in the bedroom with the same results - when the phone is used db drops and very often so does sync - even though I have a Adsl nation XTE 2005 filter on my master socket. I have found that my sync appears more stable if I add a further filter between the XTE and the phone base - but this does reduce my SNR by about 3db but would appear to stop some sync drops?

I have this theory that a lot of peoples problems are caused by DECT phones and other such devices, and that it becomes a vicious circle - sync drops, connection drops, router reloads, downstream connection subsequently drops on reload. After this happens a few times in quick succession the BT exchange thinks there are problems with the line so the Stable Rate drops straight away, subsequently download speed drops and the stable rate takes 3 days to get back up to where it started - if it does.

NB: Have also read on this and other forums about problems caused by street lights, washing machines and other devices. Not being a techie I do not understand the mechanics behind this but it may have something to do with radio waves etc. effecting SNR.

I have had 4/5 months of problems since being Max'd and now have decided that the DECT phone is a contributing factor to loss of sync.

If anyone thinks I have got this wrong please let me know.
N/A

Query: Sync speeds and Line Attenuation/SNR

Very interesting, could anyone elaborate as to why this happens?

I'm almost certain now that my low SNR is caused by all the extension wiring in the house and not some other factor simply because it is very stable at 12db occasionally it may drop to 11db for a couple of seconds.