>>pabs3+(OP)
I've never seen (or heard I guess) a kettle with a status alarm. They tend to be pretty loud when they're on, you know the water is boiled because they actually do the opposite of an alarm, the sound of boiling water gets quieter.
Maybe thats not calm tech because it requires me to listen out for it, but its simple enough and does the job
>>bodge5+wo
Have you used a whistling tea kettle? I think that's what they're referring to -- there's a small opening in the lid or spout of the kettle, and when enough steam pressure builds up inside, the steam forces itself through the opening and makes a loud whistling sound.
>>bodge5+aD
Brit here. When I was young whistling kettles were common - partly because they didn't have an auto-off-capability . If you ignored the whistle they boiled themselves dry and the room filled with steam.
I haven't seen (heard) one for years now; can't remember the last time in fact.