The super awesome feature it had was that it contained a speaker that would play the Telekom jingle every time the connection was established. This cannot be disabled and would happen at night too. So if you had a flakey connection, or used it on some other provider that still had the forced disconnect every 24 hours, it would drive you nuts pretty quickly. So I assume a lot of people took too the obvious fix to this...
German providers disconnecting customers every night is a ridiculous feature in itself. It is condescending towards customers who require to use their internet connection at night, for example because they work at night. It could lead to always-on features being broken, backups not working, and I've had countless of times where I was gaming with a German who gets DC'ed which does not work at all in competitive gaming.
In The Netherlands, yes sometimes the connection is broken at night. Sometimes, for a longer period of time. But this is because of software or hardware maintenance, and then doing such during the night makes sense as it provides the least downtime. I get that. But there is no discernible reason German providers need to disconnect every 24 hours.
It wasn't actually strictly at night, but just exactly 24h after the connection was established. But the problem was that even if you reconnected manually at a convenient time, every now and then you'd have a connection issue at a random time, and then it would keep happening at that exact time until you manually changed it again.
I'm not aware of an authoritative source for why this was the case, but most likely there must've been a technical reason like accounting, and then they just kept it around. Mind you, this only affected DSL, which at first was (apart from small regional exceptions) offered by the Telekom exclusively, and later on when resellers appeard, they had no influence on this behavior as it happened on a level where they had no access to. After a while you got consumer routers which let you choose an exact time where it would force a reconnect, so you'd at least be sure when it happened.
Ironically, when the Telekom introduced VoIP, they finally got rid of the dreaded daily disconnect, but some of the resellers kept it, like the one I'm on (cause it's cheap and otherwise rock solid). I just set it to 6 in the morning and scheduled all my backup scripts with this in mind.
While I'd have given an arm and a leg in the days of edonkey2000 for a static IP, nowadays I see the changing address as a privacy feature.
years later when I long didn't use that clock as an alarm anymore, I had it in a spot where it wouldn't properly receive the DCF signal and I noticed that it would quickly lag behind after just a few days. So my theory at that point was that sometimes the clock just managed to fall behind enough in its old spot and then resync just when the alarm would've gone off, and there was no logic to account for this. ie the clock would compare the time to the set alarm exactly once a minute, but when the clock would receive a new time signal of 7:01:00 when its local time was 6:59:59 or earlier, I'd oversleep.
I had a different situation, I sleep with roaring fans near my head and had to turn the phone alarm way up to hear it reliably. Then it would wake the neighbor at 430am whether it woke me or not. I purchased a separate 24hr timer and set the fans to go off at 4:25am, leaving a quiet room. And a quieter alarm always wakes me. Though I am now conditioned to hear when the fans shut off and get out of bed, and hardly ever fail to turn the alarm off in time.
I had a similarly flawed one. I had an alarm clock which had a MSF radio sync thing built in. But every time it resync'ed with the MSF time signal it'd make the same sound as the alarm for 2-3 seconds. You couldn't turn it off. This was invariably at 3AM or some horrible time. I eventually opened it up and cut the MSF antenna out and slept better knowing the clock was always slightly wrong.