4G Cell Phone Jammer IEEE802.11 standard defines the physical layer and media access control (MAC) specification, the physical layer defines the signal characteristics of data transmission and modulation in 2.4000 ~ 2.4835GHz band. IEEE802.11 is a wireless LAN standard IEEE originally enacted, wireless access is mainly used for hard wiring environments computer or mobile environment, because the transmission rate can reach up to 2Mbps, so business is mainly used for stored data take.
This series includes IEEE802.11a / b / g / n wireless LAN standard, which is currently used by more IEEE802.11b standard, namely WiFi. This standard specifies the wireless LAN operating band at 2.4GHZ? 2.4835GHZ, transfer rate up to 11Mbps, is IEEE802.11 a supplement. 4g cell phone jammer According to carry away Tiancheng Shizhao Zhao introduced, WiFi products in the bandwidth, interference, encryption, etc. all have a better advantage, and has a powerful network management capabilities, provides a powerful tool for large-scale network applications under real fit high-bandwidth video transmission, is currently the most widely used wireless transmission technology. It is understood that the radius of WiFi signals up to about 100 meters, you can use in the office or even the entire building, and the transfer speed is very fast.
However, insiders pointed out, WiFi is part of the standard protocol because, so users only need to support wireless laptop or PDA to get WiFi areas exist, you can high-speed Internet access, which determines its security is not very good, If more sensitive image can not be used to prevent someone else steal; In addition, their transmission distance is shorter, less flexible and therefore do not have the ability to wide video surveillance.
Therefore, based on the needs of the operator level, the 802.11 standard developed intelligent distributed technical architecture WiFi base station controller, you can achieve thousands of WiFi base station level, large-scale networking one million terminals, can be used in a wide range of areas. The 802.11n wireless bandwidth is currently the highest standard, single 802.11n wireless base station can achieve bandwidth 300Mbps, 200Mbps transmission over the effective bandwidth, enabling transmission of 200 road D1 / 1Mbps image, superior to the market the most common Fast fiber optic transmission.
In fact, 802.11 with a WAPI / 802.11i highest level of Chinese and international encryption standards, fully meet the military, financial, government high dense communications transmission requirements; their more stringent based on the physical layer, MAC layer interference, reduce error protocol standard rate-related, is the strongest anti-interference wireless standard in the standard system.
3, the wireless transmission technology of 2G / 3G 4g cell phone jammer
The transmission includes 2G CDMA, GSM mode. The two modes of low cost, have a larger coverage, and the transmission speed, CDMA in which the theoretical value of the transmission rate of 153.6Kbps, in actual use can be achieved substantially 60 ~ 80Kbps, so the wireless monitoring use, to obtain an small manufacturers. The GPRS GSM-based approach, although coverage is higher than CDMA, but the transfer rate was slightly slower, and therefore still at a disadvantage in the use.
The use of Mobile (TD-SCDMA), telecommunications (CDMA2000EVDO), China Unicom (WCDMA) carrier's 3G technology access, since 2009 onwards, by the operators to promote, many monitor manufacturers for research and development related to this area products. The prominent advantage of 3G high-speed download capability that is ideal value can reach transfer rates 3Kbps ~ 1G, but there is still in its promotion stage, so the transmission rate to be further research in this area. 4g cell phone jammer
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