Different Ways To Stop Your Cell Ringing In Certain Specified Locations

Communication jamming devices were first developed and used by the military. This interest comes from the fundamental objective of denying the successful transport of information from the sender (tactical commanders) to the receiver (the army personnel), and vice-versa.

Nowadays, mobile (or cell) phones are becoming essential tools in our daily life. Needless to say, the wide use of mobile phones could create some problems as the sound of ringing becomes annoying or disrupting. This could happen in some places like conference rooms, law courts, libraries, lecture rooms, and mosques. One way to stop these disrupting ringing is to install a device in such places which will inhibit the use of mobiles, i.e., make them obsolete. Such a device is known as cell phone jammer or "GSM jammer", which is basically some kind of electronic countermeasure device. The technology behind cell phone jamming is very simple. The jamming device broadcasts an RF signal in the frequency range reserved for cell phones that interferes with the cell phone signal, which results in a "no network available" display on the cell phone screen. All phones within the effective radius of the jammer are silenced.

It should be mentioned that cell phone jammers are illegal devices in most countries. According to the Federal Communications Commission (FCC) in the USA: "The manufacture, importation, sale, or offer for sale, of devices designed to block or jam wireless transmissions is prohibited".

Five types of devices are known to have been developed (or being considered for development) for preventing mobile phones from ringing in certain specified locations.

Type “A” Device (JAMMERS):-

This type of device comes equipped with several independent oscillators transmitting ’jamming signals’ capable of blocking frequencies used by paging devices as well as those used by cellular systems control channels for call establishment.

Type “B” Device (Intelligent Cellular Disablers):

Unlike jammers, it does not transmit an interfering signal on the control channels. The device, when located in a designated ’quiet’ area, functions as a detector’. It has a unique identification number for communicating with the cellular base station.

Type “C” Device (Intelligent Beacon Disablers):

Unlike jammers, Type C devices do not transmit an interfering signal on the control channels. The device, when located in a designated ’quiet’ area, functions as a ’beacon’ and any compatible terminal is instructed to disable its ringer or disable its operation, while within the coverage area of a beacon.

Type “D” Device (Direct Receive & Transmit Jammers):

This jammer behaves like a small, independent and portable base station, which can directly interact intelligently or unintelligently with the operation of the local mobile phone. The jammer is predominantly in receive mode and will intelligently choose to interact and block the cell phone directly if it is within close proximity of the jammer.

Type E Device (EMI Shield - Passive Jamming):

This technique is using EMI suppression techniques to make a room into what is called Faraday cage. Although labor intensive to construct, the Faraday cage essentially blocks or greatly attenuates, virtually all electromagnetic radiation from entering or leaving the cage - or in this case a target room.

Advantages:

•Police can block phone calls during a drug raid so suspects can't communicate outside the area.

•Restricts explosion of cell phone triggered bombs.
•Provides security in the business conference, board of director’s rooms, seminars, etc.
•Avoids fraud in the examination hall.
•Provides a calm and peaceful atmosphere in Hospitals, churches, temples, etc.

Disadvantages:

•Cost-oriented.

•Requires special hardware.
•People feel inconvenience.
•V.I.P.’s may lose some important calls.
•As cell phone jammer blocks all the signals within its working range, there may be grave consequences in an emergency.

Future scope:

•While the law clearly prohibits using a device to actively disrupt a cell-phone signal, there are no rules against passive cell-phone blocking.

•Companies are working on devices that control a cell phone but do not jam the signal.

Conclusion:

•Every device has good as well as bad aspects.

•In many situations cell phone jammer is useful but at many places it creates problems.
•Cell phone jammers are very useful to society for protecting from anti-social elements.
•Its overall performance is very good and helpful in our lives.