Cell block

Even the makers of cellphones now see the need to block their use on
occasion. Motorola makes some interesting claims in GB 2 329 794. “At least one
aircraft crash has been attributed to the use of a mobile phone,” the company
says, adding that there is also a danger of explosion near petrol pumps and that
mobiles cause “considerable annoyance” in theatres. So Motorola plans to put
circuitry in a cellphone that communicates with an aerial which can be hidden in
a doorway, like the metal detectors used at airports. The doorway sends an
instruction to the cellphone which shuts it down until the user leaves the
mobile-free area.