The problem
Every house has a shouting protocol. It works badly, it does not reach the garage, and it is unusable when somebody is asleep or on a call.
The modern replacement is a smart speaker in every room, which means a subscription, a microphone that is always listening, an account for each family member, and a company that can change the terms.
What paging does
Dial 500. Every handset marked for paging answers automatically and opens its speaker. Say the thing. Hang up.
No wake word. No account. No microphone open when you did not dial in. The phones are doing exactly what an office intercom did in 1975, which is the point — it is a solved problem, and the solution predates the surveillance.
Why the phone is the right device for this
It is already in every room, already powered, already yours, and already knows who is calling. A page from the kitchen handset is announced as the kitchen.
And it is a pull interface. Nothing is listening until somebody dials, which is a meaningfully different privacy story from a device whose business model requires a microphone in your kitchen.
Details worth knowing
Page-all is per handset. page = true in handsets.toml decides who is in
the group, so the guest room does not have to blare at midnight.
Intercom is the same mechanism, aimed. Dial one handset’s internal number and you have a two-way conversation between rooms, which is the version children enjoy far more than the adults expect.
Auto-answer is a header, not a hack. Asterisk sends the phone an Alert-Info that tells it to pick up. Grandstream and Yealink handsets honour it out of the box.