Why would you want one? Well we have all encountered that inconsiderate someone

who in the movie theater, restaurant or where have you, continues to
yap away regardless to the consideration of others. While most of us
just grumble under our breath, some are taking matters into their owns
hands and purchasing a yapper zapper

The cellphone jammer works by transmitting a signal on the same radio frequency used by the mobile phone.
The signals sent out by the cellular jammer and the phone collide to simply cancel each other out.

The now jammed phone will indicate that there is no service or no network signal.

Mobile
phones are full-duplex devices, which means they use two separate
frequencies, one for talking and one for listening simultaneously.

Some
jammers block only one of the frequencies used by cell phones, which
has the effect of blocking both. The phone is tricked into thinking
there is no service because it can receive only one of the frequencies.

Less
complex devices block only one group of frequencies, while
sophisticated jammers can block several types of networks at once to
head off dual-mode or tri-mode phones that automatically switch among
different network types to find an open signal. Some of the high-end
devices block all frequencies at once, and others can be tuned to
specific frequencies.

To
jam a mobile, all you need is a device that broadcasts on the correct
frequencies. Although different cellular systems process signals
differently, all cell-phone networks use radio signals that can be
interrupted. GSM, used in digital cellular and PCS-based systems,
operates in the 900-MHz and 1800-MHz bands in Europe and Asia and in the
1900-MHz (sometimes referred to as 1.9-GHz) band in the United States.

Jammers
can broadcast on any frequency and are effective against AMPS, CDMA,
TDMA, GSM, PCS, DCS, iDEN and Nextel systems. Old-fashioned analog cell
phones and today’s digital devices are equally susceptible to jamming.

The
cell phone jamming device, oftentimes disguised as a typical mobile
phone will block cell phone signals within a range of upto 30 feet.

Sometimes
refereed to as a cell phone blocker cell phone jammers where developed
originally to allow law enforcement officials to interrupt
communications by criminals.

A cell phone jamming device is ideal
for meeting rooms, conference rooms, museums, galleries, theaters,
concert halls, churches, temples, restaurants, classrooms, training
centers, factories, banks, trains, buses etc or if you want to avoid
information being disclosed secretly during meeting and anywhere else
you need peace and quiet.