posted 02-14-2003 02:29 PM                    

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Again, some enterprising company should build a device that detects the "handshake" (locating) signal of any cell phone operating in close proximity to it, sounding an alarm. Such a device next to the ticket-taker would allow theatre personnel to politely ask for the customer to turn the cell phone OFF before entering the theatre.

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• Install a micro mobile phone base station next to your detector and as it comes into range it should (if I understand how they work) check in. This is probably a non-starter as it would be very expensive and almost certainly require a transmitter.
• Make them walk through an area that has no signal, so there phone checks in when they come out. Quite how big this would have to be to work I'm not sure, but there shouldn't be any problem.

As regards detecting phones, my PC speakers occasionally pick the handshake up when I'm sat at my desk, so it can't be too difficult to detect.
More plausible (I think) would be a system in the auditorium which detects and localises a phone (whilst handskaing or making/recieving a call). I guess you would you use direction finding recievers or look at phase diff's between recievers. Then you could identify the offender for suitable punishment at an appropriate point. I quite like the idea of a localised sprinkler system.

It also occured to me whilst writing this that if the handshake contains the telephone number of the handset you could phone them and ask them to turn their phone off.

John

P.S. Sorry that this message was originally truncated. Not sure what went wrong (though I suspect the spell checker lost the last paragraphs) but I should have checked before leaving it.

[ 02-14-2003, 03:41 PM: Message edited by: John Moriarty ]

posted 02-15-2003 05:29 PM                       

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from Michael G.:
... the point of my legal argument is that if it is illegal to have a cell phone in a theater... then a theater's management could not get into trouble for having a jammer because legally there should be no signals to jam... This is what we call a legal loophole.

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posted 02-17-2003 02:42 PM                       

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There is a company that has designed interior wall panelling which won't allow cell phone frequencies to pass. Passive methods such as this one are currently legal in the US, though the last article I saw on the subject indicated the panels were still pretty expensive.

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posted 02-18-2003 08:32 AM                    

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if speakers such as computer speakers can detect a "handshake" signal when a call comes in on a cellphone, why wouldnt larger speakers such as those in a theater be able to detect that and why you cant hear it?

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