Movie Theaters Try to Keep Things Quiet

Other companies, mostly operating outside of the United States, make devices that basically jam or overcrowd the network, as when too many people try to make calls at the same time, said Roger Entner, a wireless analyst at Ovum, a research firm.

"The problem is that jamming doesn't stop where walls are," he said. "You're always bleeding out to other areas," such as the street in front of the theater, which would prevent a passing driver from making a call.

Macdowell said the theater owners' association is also exploring technologies that disable ring tones but quietly notify users of incoming calls.

Cell phone providers, meanwhile, prefer to encourage proper etiquette.

Cingular Wireless, for example, sponsors pre-movie advertisements mocking its "Inconsiderate Cell Phone Man," which the company says encourage viewers to turn off their phones.

"Research shows the vast majority of consumers take action" with a simple reminder, said Cingular spokeswoman Rochelle Cohen.

Entner, who has a young son, said blocking cell phones could backfire because people like him would simply stop going to the movies.

"Instead, I'll wait a couple of months and get the DVD for 20 bucks," he said.