A couple of questions I was afraid to ask....

These things have always puzzled me:
a) had a Thompson adsl router. On my 2Mbps fixed line the noise margin would be high after a reset and then slowly decline over days until I had to reset it again. The new dlink router doesn't seem to need this periodic refresh. Can anyone explain the technicalities?
b) why do upstream and downstream attenuation figures differ ? Surely its the same piece of wire ?

Thanks to anyone kind enough to answer.

a) Don't know but do you mean a Router or a Modem (e.g. Thomson Speedtouch 330)?

b) Generally Down Attn. = about 2 x Up Attn. This is because Up uses much fewer frequencies than Down.

...and the up frequencies are lower and are attenuated less.

Thanks. It was a Thompson 560 if I recall, adsl modem/router.