Mobile phone blocker is a device that is used to prevent mobile phones to receive the signal from the stations. It can be used at any place but this is more commonly used at a place where receiving a phone call is undesirable because it would be better to maintain silence at that place.
These hammers or phone blockers transmit signals actively these are banned at some places based on the laws of those areas. According to the federal communication commission use of phone blockers or similar instruments which are devices to knowingly block the signals are illegal and doing so will be a violation to this law.InU.S. It is not even illegal you buy these jammers or blockers but also illegal to sell one.But those who want this get it from overseas market.Only government employees are authorized to buy these blockers.There are some places where these phone blockers can work like theatre where someone receives a call and continues talking at normal volume as if no gets disturbed the. For such people only theatre should have this device installed.Also there are so many workplaces where some people continue talking like normal like at warehouse or assembly like where only emergency calls should be allowed.So movie theatre, concerts,churches etc. are some places who suffer due to cell phones.A phone blocker broadcasts same radio frequency as that of a cell phone which disturbs the communication between the mobile bases station in the tower. The blocker then says no to the phone users within the range of the phone blocker.These devices generally occupy the phone by broadcasting a signal at the same frequency and such a power that the signal between base station and the phone cancels each other.
Cell phones have full duplex services which imply that there are two separate frequencies,one for talking and the other for listening simultaneously.So it disrupts the frequency of either of the side which automatically disrupts the frequency for the other side.When the phone blocker is inactive or on mode then most phones will automatically direct to no network mode or no signal mode.After the blocker is turned off the phone resumes its signal strength .Some factors which affect the working of. Mobile phone blocker is humidity,temperature,tower distance etc. There is a type of jamming method in which the device acts like a detector and in order to establish a communication with tower the blockers uses a identification pin and when the signal is broadcasted from the base station.The blocker identifies the pin and then signals the tower not to make a communication which is further prevented by software at base station.