>
>  The problem is that in general a "cell" does not match up with the
>  "quiet zone" area.  But something like this ought to be possible to
>  implement now that phones are incorporating more "local" connectivity
>  such as 802.11 or even bluetooth.  And the GPS on other phones might
>  come into play as well, even if the connectivity isn't as localized.
>  (hmm.  Wonder if that's worth updating the patent?)  All you really
>  need is a way to determine that the phone is IN a "quiet area" and a
>  way to tell it to be quiet.


Inductive loop signalling.  Pickup is great inside the loop and next
to nothing outside it.
Plus you wouldn't need FCC approval, just use some nice low frequency.
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