I seem to have a speed / reliability tradeoff with my Billion 7300G ADSL modem.

If I enable ADSL2+, the internet drops out many times a day.

If I enable only ADSL2, then I get slightly slower speeds (I’m quite far from the exchange), and dropouts happen every few days.

I then stumbled upon a “secret” menu:

http://{modem IP address}/iptv.asp

The “noise margin” drop down list gives you options of: Normal, IPTV, Maximum line rate, test lab 18, IPTV2, Others

Its currently set to “others”

I try a few settings, and these are the results:

Normal: 4093 kbps, noise margin (downstream): 7.2db

Maximum line rate: 4594 kbps, noise margin (downstream): 6.3db

test lab 18: 4775 kbps, noise margin (downstream): 6.1db

others: 4824 kbps, noise margin (downstream): 5.2db

This explains why many 5200G owners say its a very fast modem, but it works best if you are close to the exchange.

As the speed increases, the noise margin decreases and (I assume), the chances of a dropout increase due to changes in line characteristics.

So I decide to move from “others” to “maximum line rate”, and also change from ADSL2 to ADSL2+ (although I haven’t noticed any difference between ADSL2 and 2+).

After a few days, it looks like the modem is much more stable… no dropouts at all… its worth it for a slight drop in speed!