I am currently on my 3rd DSL modem in this house (well, many more if you count the ones Alcatel 1000 and the Netopia 2200H routers that were retired as they could not support the 6Mbps throuh-put).
My first modem was an Alcatel Speed Touch Home that I purchased off of eBay in January 2006. This modem allowed me to use the full bandwidth of my 'Fast Access Extreme' DSL Line.
It worked reliably for about 2 years- until the Tornado hit Atlanta in March 2008. The modem was not obviously damaged, but it could not keep a sync and kept dropping and reconnecting. After talking to BellSouth support, they replaced it with a Motorola 2210 DSL modem:
This little guy seemed to be a bit zippier than the Speed Touch Home (probably just an illusion as it was new). The first guy worked like a champ until late October when the roommate forgot to pay the electric bill. After power was returned, it exhibited the same issues as the earlier Speed Touch Home; sync drops every 15-20 minutes.
After conversing with BellSouth they again determined it was my DSL modem and replaced it with a like Motorola 2210- which fixed the issue for another 3 months.
Last week we had another power outage that lasted long enough to drain the UPS that the DSL modem was attached to- and now I am having very similar issues...
I am starting to see an issue where a DSL modem cannot go through a deep discharge of a UPS system and function properly after power is returned. This seems very strange as I thought UPS units were designed to protect the device rather than kill it.
I have dug out an old Netopia 3347WG router out of the attic and I am now using it for a DSL Modem with my D-Link DGL-4500 set to DHCP Ethernet mode instead of PPoE (which is now handled on the Netopia). I am doing a double-NAT, but everything seems to be working for them moment...