Actually, the key to silencing of terrestrial cellphonitis is contained in AAFF's excerpt:

"...an on-board EMI screening system stops the cellphones contacting the ground network."

Surround your theater or restaurant with a Faraday Shield (a late 19th-century Cone of Silence) and the cellphoners might as well be on Mars.

Where to buy:

Bose Quietcomfort - Crutchfield $299

Sennheiser PX250 - $80 refurbished from Tigerdirect, or $99 new from Heartland America.

Sennheiser PX300 - $136 from LCDTV.com

Sony MDR-NC11A - Amazon.com (actually various merchants through them) ~$74.

Shure E2c - $76 from plasmabay.com

Shure E4c - $183 from erwincomp.com or digitalfotoclub.com

[E3c will cost between the two, and E5c above all. There's also the new "i" series that have plugs and connectors for both mobile phones (how ironic!) and music.]

More merchants and prices from shopping.com or other shopping blogs.

Jammers <i>do</i> know exactly how the energy is spread over the spectrum by legitimate transmitters; that's why they work so well. And some types of jamming don't require interfering directly with the signal from other handsets at all.

Companies that build jamming equipment know just as much about the transmissions to be jammed as the companies building the transmitting and receiving equipment. They don't have to guess.

Anyway, jamming is not a good idea on an airliner (or anywhere else). It's not very selective, it can &quot;leak&quot; into other channels in some cases, and it can interfere with safety-of-life applications (assuming that the purpose of the jamming is not to put anyone's life in danger).

I assume this very old thread was topped by an advertiser. It is instructive of the changes in mobile phone use over the past seven years, if nothing else.

It is instructive as to the fact that there are still a lot of people who do NOT have any desire to hear someone else's one-sided conversations.