There are millions of cell phone users and their numbers are growing. Each individual has one or more. These are used for different purposes. Very few people do not use these for personal reasons.
You must understand that you are meant to use something and not abuse it. There are places where you are not supposed to use your phone. Your phone usage is helping you alone.
A Jammer is a blocking device for cell phones, which sends the blocking signals to towers from the same frequency range of the cell phones, the interference cause the cell phone to lose the signals from the station.
But the main problem is a Jammer cannot be detected. Your phone will remain in poor signal reception if a Jammer is active in the area. The Federal Communication Commission of the United States (FCC) has control over broadcasting public telecom services.
A telecom company hires a certain frequency range and pay for it. Blocking the signal, means compromising on the reliability of service. Leads to offenses like a theft of property. Apart from that there are over 100,000 – 911 calls are made daily using cell phones in the US alone. So using Jammer is illegal and so it is punishable by law.
The use of cell phone jammers is prevalent in the area of Schools, Theatres and restaurants although the law opposes it. Actually no one can detect it is being used as you will only get poor signal strength in your cell phone.
Handheld cell phone jammers are readily available online for $250 and more according to its range. Some cell phone companies encourage education in mobile etiquette rather the using cell phone jammers. They think this is an alternative way to stop cell phone usage in the prohibited places.
The phone jamming
People use the phone for their needs. They do not realize that it is their need. You might use it for your purpose, but you have no right to disturb or offend anyone with you chatter.
To restrict these, jammers are used. The jammers transmit radio frequencies identical to those use by cell phones. The signal prevents communication between the cell phone device and the cell phone base tower. Thus, the service is not available.
The legal part
In America, it is not permissible legally. It is treated as interference in the service provided by a licensed authority. It can even be considered as theft. You must take care of the fact that you are not violating any law.
That might put you in trouble. Along with that, there are certain annoying people who are causing the disturbance. A jammer does not work preferentially. So, you cannot deprive all the people for certain individuals.