Q: Some universities use cellphone-dampening devices in their classrooms to block all cellphone signals. Are these devices affordable for the home user and, if so, where would you find one for purchase?
- Richard Chandler, Tucson
A: Cellphone jammers are radio broadcasting devices that block cellular phone calls within a radius of 30 to 160 feet. They are illegal in the U.S., and I can't find any news reports of jammers being used in U.S. universities.
But you may have read earlier this month that researchers at Anna University of Technology in India have developed a low-power jammer designed to prevent drivers, but not their passengers, from using a cellphone while a vehicle is in motion.
It's unclear whether cell-jammer technology will ever be adopted in this country. The Federal Communications Commission says "it is a violation of federal law to use a cell jammer or similar devices that intentionally block, jam, or interfere with authorized radio communications such as cellphones, police radar, GPS and Wi-Fi." The FCC explains the law on its website at www.tinyurl.com/8296prf/
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Why the strong stand against jamming wireless calls? The FCC says that jammers not only disrupt authorized radio services, but also jeopardize critical public safety communications, such as 911 calls, and could compromise law enforcement efforts.
E-mail tech questions to steve.j. alexander@gmail.com; please include a full name, city and telephone number.