Detection of a specific sound

[Random832]

Dennis Lee Bieber <wlfraed at ix.netcom.com> writes:

> If a fire did occur, and the inspectors find traces of wiring
> going into what was supposed to be a stand-alone detector there is
> a risk that it will be concluded that the detector had been
> tampered with and may not have been functional... And that could
> lead to all sorts of liability problems.

What about a *second* smoke detector?