Beefing up a door bell

[JNugent]

If it's a wireless unit, why not just buy another one, to be placed in an additional location, paired to the same bell-push?

[Owain Lastname]

There were ones designed for repeating telephone bells, as in those days you couldn't connect to the phone line.

The microphone under the telephone triggered the circuit but only from a loud noise, ie the telephone bell ringing. It didn't activate on ordinary background noise or conversation.

Don't know if this circuit actually works, but it's the idea.

Owain