by Bob Walters | March 01, 2007

Several years ago, when I was giving a presentation to a large group in Washington, D.C., I was making a key point when a cell phone belonging to an attendee in the second row starting ringing. It was one of those irritating ring tones that kept getting louder, causing the owner to get increasingly flustered and embarrassed as she struggled to find the phone in her purse.

I politely said, “If it’s for me, please tell them I’m busy and take a message.” It was easy to make a joke back then, when cell phones were still somewhat novel and interruptions weren’t commonplace. Today, however, given an ever-increasing array of communications devices, it’s not just the audible call that becomes the interruption but also the text message or
e-mail. In the past, if people were looking down intently, they likely were taking notes; today, they more likely are composing a message, responding to one or even surfing the web.

Around the World

What can be done to stop the distractions, short of having attendees check all cellular devices at the door? In the United States and most of Europe, it is illegal to intentionally block or interfere with any RF (radio frequency) transmissions. But consider the uses where it is legal:

* In Mexico, churches use jamming devices to prevent signals inside their walls.

* In France, cell phone jammers are used as a common practice in offices, theaters and public buildings.

* In Latin America, signal jammers are used to prevent people inside a bank from alerting muggers outside to customers who have withdrawn large sums.

Use them at your own peril in the United States, however: The Federal Communications Commission can fine you up to $11,000 and send you to prison for up to a year. However, to date no one has been prosecuted under this law, and several efforts are underway to change the law to allow selective blocking.

Legal Means

In the meantime, the most direct method is the polite request: At the beginning of each session, remind participants to shut off their phones and PDAs.

Beyond that tactic, which is flawed by human nature, following are several possible solutions for curbing signals. Check to see if potential meeting sites use the following.

* Magnetic wood paneling. A scientist has created a building material saturated with magnetic particles of nickel-zinc ferrite that blocks 97 percent of cellular signals.

* Faraday Cage. Named for physicist Michael Faraday, this involves creating a room or area that is a self-contained electrical barrier that shields incoming or outgoing signals.

* Lead-painted walls. Of course, there are health concerns associated with chipped and peeling lead paint, but just for the record, such paint limits the signals going in and out of a room or area. Older buildings such as hospitals or historic landmarks might still use it (and must pass health inspections).

* Q-Zone. This product, made by BlueLinx Inc. ( uses Bluetooth technology to change the ringing characteristics of phones to create a quiet zone. Depending on the phone, the Q-Zone might set the ringer to vibrate, lower the ring volume or direct inbound calls to voice mail. Once a phone leaves the quiet zone, it returns to normal operations.

Q-Zone is available on a subscription basis and can be deployed legally in a wide range of environments, with costs determined by the size of the quiet zone desired. It will, however, work only on Bluetooth-equipped phones.

Until the laws change or more facilities deploy tools like the Faraday Cage or Q-Zone, our main defense against these annoying interruptions remains a courteous and cooperative audience.

Bob Walters,based in Fort Worth, Texas, is founder of Phoenix Solutions and developer of MeetingTrak Software.