cell phone jammer is widely used in the examination by the school

the students can use the cell phone and cell phone jammer should not work after class.
Fiber distribution of the system using optical fiber as the signal transmission medium, the system structure can be simply represented by Figure 4. Downstream signals by the photoelectric device to convert the optical signal by the photosynthetic road / splitter, fiber optic transmission to the distribution point, then optoelectronic devices convert the electrical signals sent to the distribution of antenna out. Uplink signal is launched in the same way back to the base station. Ordinary cable is the most commonly used option, its advantage is to use a wide frequency range and large coverage and cost of low-cost, mainly used in underground shopping malls, underground parking, multi-storey office buildings, hotels and large shopping malls. Nowadays,  cell phone jammer is widely used in the examination by the school.
The characteristics of these places is the blind spot area, but all blind spots isolated from each other and relative dispersion, using ordinary cable program is to effectively solve the complex internal structure of buildings and the need to cover the region is relatively fragmented. The advantage of using leaky coaxial cable is the field strength and uniformity, according to the design of effective control of coverage applicable to the lift of the long and narrow area, such as subways, tunnels and skyscrapers. In particular, in the subway and the tunnel due to the corners, plus the carriage block radio transmission, only the use of leaky coaxial cable in order to ensure the transmission will not be interrupted. For optical fiber, because the signal is transmitted via optical fiber to the entire antenna. The customer should screw the antenna of  cell phone jammer tightly and correctly.
Cable, almost can not consider the loss of signal in the transmission optical fiber transmission loss is much smaller than the cable transmission loss, so you can avoid the long distance area due to the ordinary cable or cable leak have to add too many amplifiers in the system resulting in the introduction of noise and intermodulation. Therefore, the way of fiber relative to the first two ways, has its obvious advantages: the signal transmission performance, not placed in the building a long-distance cable, easy installation; but also its fatal flaw; more expensive because of the optoelectronic devices make The total system cost is too high. By pressing the switch on the host of  cell phone jammer .