Cell Phone Jammers Are Classified By Frequency

4G LTE 725-770MHz

4G 790-862Mhz

4G 2300-2400MHz

4G 2620-2690Mhz

CDMA 850-894MHz

GSM 925-960MHz

DCS 1805-1880MHz

PCS 1920-1990MHz

3G 2110-2170MHz

Mobile communication is also called cellular mobile communication. As far as mobile phones in each cell are concerned, they communicate with the base station through the uplink frequency of the channel, and then transfer the signal to MSC to communicate with other mobile phones or fixed phones; The wireless frequencies received by mobile phones are divided according to the frequency bands:

GSM segment 925-960MHz, DCS segment 1805-1880MHz, CDMA segment 869-894MHz, PHS 1900-1990MHz, SCDMA450-470MHz, wCDMA2110-2170MHz, TD-SCDMA2010-2025MHz. Each frequency band is divided into many channels with a certain bandwidth. Each cell uses several channels, one of which is called the broadcast control channel, denoted by BCH, and the other channels are called business channels. In the standby state, the mobile phone intermittently starts the receiving circuit to receive the BCH in the cell. According to the field strength of the BCH signal, the signal strength indicator RSSI is displayed on the LCD with the signal bar. When making an outbound call, first ask the MSC for instructions through the BCH, and the MSC will handle the calling or called, and the MSC will allocate a service channel to the mobile phone according to the channel conditions in the cell, so that the mobile phone can jump from the BCH to the service channel to realize the call. From this point of view, the BCH in the community is the medium and prerequisite for realizing mobile phone communication. If the mobile phone cannot find the BCH in the community, there will be no screen name and signal strength indication on the light screen LCD, that is, the mobile phone will be in the state of no network, no The state of network access, so the mobile phone cannot realize the function of calling or called, that is, the mobile phone signal is equivalent to being blocked.