Can signal alerters replace cell phone jammers?
Signal alerters are available that indicate the presence of a cell phone signal. These have been used in hospitals where cell phone signals could interfere with sensitive medical equipment. When a signal is detected, users are asked to turn off their phones.
Physically block signal transmission and reception.
While the law prohibits using a device to actively disrupt a cell phone signal, there are no rules against passive cell phone blocking. That means using things like wallpaper or building materials embedded with metal fragments to prevent cell phone signals from reaching inside or outside the room. Some buildings have designs that block radio signals by accident due to thick concrete walls or a steel skeleton.
Signal interception system?
Companies are working on devices that control a cell phone but do not “jam the signal.” One device sends incoming calls to voicemail and blocks outgoing calls. The argument is that the phone still works, so it is technically not being jammed. It is a legal gray area that has not been ruled on by the FCC as of April 2005.
Most of these methods can only be imagined, not practical, and the cost is too expensive.So it makes sense to obtain legal information about cell phone jammers.