Chris J Dixon wrote:

Somebody recently remarked that it wasn't working, and I
demonstrated their error, commenting to them that I thought the
point was to put it where _I_ could hear it. The indicator light
flashes, but is clearly not trusted.

Their error! Good god, if I didn't knock everytime I couldn't hear a
wireless door chime I'd never get a reply. True the battery in the push
last well, but the ones in the receiver (which are almost always battery
powered) are, more often than not, flat[1] which the owner never seems
to realise.

Bloody things. 4 x C-cell Friedlands rule. Batteries last donkey's years.

Soott

[1] And when they're not flat, the receiver will be randomly unable to
receive the signal.