Does anyone here have any experience with using 900MHz RF data devices?
I'm looking for a short range (<20ft) transmit/receiver pair that can
easily be used to send an "activation" signal.  This would be for use in
a consumer product, so FCC approval is essential.  I've seen various 314Mhz
devices [e.g. the Ming thingies] which would be adequate except that they're
not FCC approved and I can't find any specs about what one can transmit at
that frequency.  The 900Mhz band is basically a free-for-all, and at 20' it
shouldn't be too hard for a transmitter to win out over other users of that
band.

BTW, this application won't necessarily be line-of-sight.  If it were, I'd
use infra-red.