The intense popularity of cell phones during the past 20 years often leads to the interruption of various activities that require silence. Have you ever heard a cell phone ringing at a funeral, in a hospital, during exams or other places where quiet is needed? Older model analog phones often had poor reception so they could be disabled with the use of high frequency noise. Also, the use of Faraday Cages has shown to prohibit external electric fields and are employed by law enforcement and the military to interrupt terrorist and other illegal activity. Newer mobile devices require more high-tech measures.
Numerous countries around the world do not allow the use of cell phone jammers. However, some governments allow the use of such devices in movie theaters, music halls and other performance sites. Some schools in Europe use this technology to prevent cheating on exams.
Manufacturers are developing technology that will control a cell phone but do not actually jam the signal. Some devices send all incoming phone calls to voicemail and prevent outgoing calls. Cell phone alert systems are made which indicate the presence of a cell phone signal. These devices are often used in hospitals where valuable medical equipment could be affected cell signals.
While the law says we cannot use a device to actively stop a cell-phone signal, no rules exist against passive cell-phone blocking. Some businesses use wallpaper or building materials that have metal fragments inside them to block cell-phone signals from reaching inside or outside the room. Some buildings designs block radio signals by accident due to thick concrete walls or a steel skeleton.
A fun solution can be found at the Society of HandHeld Hushing. They've got a note on their website that you can print out and give to people who carry on loud, obnoxious cell phone conversations. How many times have we all wanted to do this?
When I do use my cell phone I scope out the area nearby to see who may be listening. At least I'm trendy when I talk on my phone. My device has a cuddly cell phone cover that even has a rugged key-clip attachment so I can't lose it. The phone is tightly fastened to my gym bag. If I happen to drop it, the phone will just bounce. The cover also protects it from scratches. All my friends want one too.