Keeping Phones Quiet
By Carlo Longino, Thu Apr 08 16:00:00 GMT 2004

A number of companies are working on technology to silence mobile phones -- whether the user wants to or not.

We've all been in a movie or some equally unsuitable place where somebody's phone rings, and chances are most of us have been in one of those places when somebody decided it was an okay time to talk on their phone too. For some venues, signs or even laws aren't enough. They're looking for ways to actively render mobiles temporarily useless.

Phone jammers have been around for quite some time, even though they're illegal to use in many countries. A guy in the UK showed me one he carries, and said it was perfect for the train ride home when somebody's carrying on a conversation that's too loud, as the jammer was just strong enough to make a dead zone of one train carriage.

Evidently some businesses have bigger worries than simple annoyances: casinos are worried about phones being used to cheat, prisons want to ensure phones aren't used by inmates for nefarious purposes and any number of places are worried people are using cameraphones where they shouldn't be.

One company, Bluelinkx, has technology called Q-Zone that uses Bluetooth to put phones into silent mode. While this type of silencing is probably the most reasonable, a phone must have the Q-Zone software installed on it, as well as having Bluetooth (and turned on to discoverable mode, presumably), so it's hard to see it becoming popular or effective.

Another company makes a "Cellphone Detector Plus" that detects mobile use and transmissions and sounds an alarm. It can then play a voice message admonishing users to turn their devices off. Other companies are selling building materials that are impervious to certain radio waves, like wire mesh screens mounted inside walls, or concrete with conductive mixtures that provide interference.

Looks like these companies are hoping bad manners pay off.