"noise margin is the most useful number.." OK - mine is up/down 12.0/13.5dBs is that good or bad? What can I do with this gen?
Something is wrong then, if you only get 0.5mbit/s with a 12dB noise margin. If the line could, it would trade off the higher noise margin for faster speed until it got down to 6-7dB and sit there.
However, since your neighbour gets speeds in the order of magnitude greater than yours, you should be fixable.
Firstly, would you like to PM me with your line's phone number, as i'll then run it through the checker and see whether there's anything that stands out glaringly?
Secondly, who is your ISP?
Thirdly, has BT ever offered to swap line pairs at your house?
I would strongly recommend with the big disparity in numbers here, to do the connection to the router at the master socket's test socket. (see
How to test your ADSL in the Master Socket for how to do this).
Cheers,
Mike.