Alleged misuse of cellphones by Pappu Yadav, MP, RJD in Beur Jail led
the Supreme Court to permit the installation of mobile phone jammers in all
jails across the country.
A division bench comprising of Justice N Santosh Hegde and Justice SB Sinha
has asked mobile service providers, Bharat Sanchar Nigam (BSNL) and Reliance
Infocomm to inform the court on how this facility could be installed in the
central jails, to begin with, for preventing "highly influential and
powerful personalities from misusing mobile phones while being lodged in
jail".
This misuse has to be stopped across the country in all jails and the process
could begin by installing jammers at the central jails, the bench
observed.
What are Jammers?
So, what is the basic functionality of jammers? Jammers are high frequency
transmitters deployed for blocking mobile signals from reaching BTS (for
outgoing calls) or mobile phones (for incoming calls).
The jammers can act as a virtual transmitter and interfere with the normal
working of cellphones, blocking both incoming and outgoing calls. Depending upon
the functionality, jammers can block radio frequency in one particular band (GSM
or CDMA) or sets of bands (GSM/CDMA/VHF/UHF).
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Used mainly by military and law-enforcing agencies, deployment of jammers is
considered illegal in most of the countries. The primary goal of jammers is to
block cellphones in areas where they are forbidden by law, such as jails and in
other places where it creates a nuisance, such as: churches, theatres, concerts
halls, or conference halls.
Jammers Vs Interceptors
For jails, service providers can opt for either of two solutions-detectors
or jammers; and interceptors. In the first case, radio signals are detected by
putting detectors in different cells, wherever required, and when the signals
are detected it jams the signals.
This helps in jamming a particular area of the jail where prisoner movement
takes place rather than jamming the entire jail and affecting the entire
communications system. Its cost ranges between $5,000 and $35,000.
Also, service providers can opt for interceptors that are currently in use by
majority of the jails worldwide. Considered to be an intelligent device, the
interceptors act as an all in one device and perform functionalities of a
sensor, jammer, and recording system.
So, depending upon the conversation, one can either jam or record. The
intelligent system costs are on a higher side and it is in the range of
$200,000.
Deploying Jammers/Interceptors
But before deploying any of the two solutions, the service provider has to
do a site survey to test the signal as is done in the case of installation of
BTS. Since, jamming range is a function of signal strength received form a
nearby base station and varies from one location to another. Even the jamming
range varies with respect to different networks in a given location. Jamming
also depends on topography of that area, thickness of the wall,
reflection/absorption of signals in the given area, area to be covered, and
frequencies to be jammed.
Once the survey is done, the service providers are in a better position to
design an efficient system by knowing the number and positioning of the jammers.
The service providers can either opt for a particular frequency band (GSM/CDMA)
or can opt for a mix of VHF/UHF/CDMA/GSM/satellite phone/WI-Fi/Bluetooth/DECT.
Care should also be taken to see that in case of power failure there are
adequate backup facilities so that the jamming/interception systems can function
even without assured power supply.
Once all these factors are taken into account, service providers can ensure
that jamming/interception system is foolproof and will also help in preventing
highly influential and powerful personalities from misusing mobile phones while
being lodged in jail.