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[blwarburton]

Just had my ISP change connection from Annex A to M upload.
I was expecting more upload bandwidth than I'm getting.
Upload bandwidth has changed from 1300Kbps to 1728Kbps with a dip in the upload as seen in the DMT picture.
I was expecting 2000Kbps upwards.
Re-booting the router sometimes gives a slightly higher figure of 1800Kbps at 5db SNRM upload figure.
Is there anything that the DMT tool can do to raise the upload bandwidth ?
http://i250.photobucket.com/albums/gg276/34blw/dmt20080413_0943.png

[attachment deleted by admin]

[guest]

Looks like there's something generating noise on the upstream.

Do you have all phones disconnected and the router plugged into the test socket?

The test socket is shown here - http://www.kitz.co.uk/adsl/troubleshooting.htm

Edit - the DMT tool is no use for modifying upstream settings on Be. I tried when I was there

[blwarburton]

I've fitted an ADSL face plate to the NTE5 master socket. The router sits next to the master socket. All the phones are disconnected. The ring line 3 is disconnected from all sockets in the house. I live about 1 mile from the exchange. The ADSL face plate raised the download bandwidth from about 12000 to 15000Kbps with fewer missing gaps. I was expecting Annex M to double the upload bandwidth but I only see about 30% improvement. The actual upload speed (in Kb/s) hasn't changed much - from about 115Kb/s to 140Kb/s.

[blwarburton]

I assume there's digital upload/download filters at the exchange - maybe in the DSLAM.
When switching from Annex A to M, I assume the ISP re-program the filters cut-off to a different frequency.
It looks like the upstream filter isn't compensating for the signal loss at the higher upstream frequencies.

[blwarburton]

Be have turned down the SNRM to 3dB at the exchange giving a bit more upload (and download) bandwidth.
Here's the picture:
http://i250.photobucket.com/albums/gg276/34blw/dmt20080413_1817.png
The DSL signal may drop out if there's a lot of noise. Hopefully with the ADSL filtered at the master socket it should be ok.


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[guest]

3dB is a bad idea IMHO as you have little to no resilience against impulse electrical noise.

"I assume there's digital upload/download filters at the exchange"

No.

Annex A (Be's normal ADSL2+ service) uses frequencies from 25-138kHz to provide the 1.3Mbps upstream. From 138kHz to 2.2Mhz is downstream.

Annex M extends the upstream to 25-276kHz to provide a maximum 2.5Mbps upstream. Downstream loses the frequency bins from 138-276kHz and so should drop a little.

It sounds like you've done all you can inside your property in terms of wiring. Have you tried turning EVERYTHING apart from your PC and the router off at the mains to see if that helps?