Wi-Fi is commonly known as wireless broadband. The so-called Wi-Fi is actually another name for IEEE 802.11b. It is an industry term published by an organization called "WECA", which is translated into "wireless compatibility certification" in Chinese. It is a short-distance wireless transmission technology, which can support the radio signal of surfing the Internet within hundreds of feet. With the development of technology, IEEE 802. 1 1a and IEEE 802.1g appeared, and the standard IEEE 802. 1 1 has been collectively referred to as Wi-Fi. From the application level, to use Wi-Fi, users must first have a Wi-Fi-compatible client device. Wi-Fi is a technology that can help users access e-mail, internet and streaming media. It provides users with wireless broadband Internet access. At the same time, whether at home, in the office or on the road, it is also a quick and convenient way to surf the Internet. Places where you can access Wi-Fi networks are called hotspots. Wi-Fi or 802. 1 1b works in the 2.4Ghz band, and the maximum supported rate is 1 1Mbps. 802. 1 1 Space also has two protocols, including (a) and (g). They are also publicly used, but 802.438+0438+0b is the most commonly used in the world. Wi-Fi hotspots are created by installing an access point on an Internet connection. The access point transmits wireless signals over short distances, usually covering 300 feet. When a Wi-Fi-enabled device (such as Pocket PC) encounters a hotspot, the device can wirelessly connect to the network. Most hot spots are located in places for the public to visit, such as airports, coffee shops, hotels, bookstores and campuses. Many homes and offices also have Wi-Fi networks. Although some hotspots are free, most stable public Wi-Fi networks are provided by private Internet service providers (ISP), so users will be charged a certain fee when connecting to the Internet. The full name of a notebook that supports Wi-Fi is Wi-Fi. 802. 1 1b is sometimes mislabeled as Wi-Fi. In fact, Wi-Fi is a trademark of WLANA, which only guarantees that the goods using the trademark can cooperate with each other, and has nothing to do with the standard itself. But people are getting used to calling 802.6438+0 1B protocol with WIFI. Its biggest advantage is its fast transmission speed, which can reach 1 1Mbps. In addition, it has a long effective distance and is compatible with various existing 802. 1 1 DSSS devices. Notebook technology-Centrino technology is based on this standard. IEEE (Institute of Electronic and Electrical Engineers) 802. 1 1b wireless network specification is an extension of IEEE 802. 1 1 network specification, and its maximum bandwidth is12Mbps, which can be adjusted in case of weak signal or interference. Its main features are: high speed and high reliability. In the open area, the communication distance can reach 305 meters, and in the closed area, the communication distance is 76 meters to 122 meters, which is convenient to integrate with the existing wired Ethernet and has lower networking cost. The official name of Wi-Wi-Wi-Fi(WirelessFidelity) is "IEEE802. 1 1b", which, like Bluetooth, belongs to short-distance wireless technology used in office and home. Although this technology is worse than Bluetooth technology in data security, it is slightly better in the coverage of radio waves. Wi-Fi coverage can reach about 300 feet (about 90 meters), and it goes without saying that offices can also be used in smaller buildings. Therefore, Wi-Fi has always been the preferred technology for enterprises to realize their own wireless LAN. Another reason is that Wi-Fi seems to be better than the expensive 3G enterprise network. The hotspots about Wi-Fi were all born in 2002. In the United States, Wi-Fi, like the early Internet, shows the trend that a single spark can start a prairie fire. In 2003, it is destined to have a bright future in the world. The high-speed wireless Internet access brought by Wi-Fi will be as common as people using mobile phones today. At present, manufacturers are actively applying this technology to all kinds of devices from handheld computers to desktop computers to create new selling points. As the number of Wi-Fi devices increases, its price will drop. In 2006, the global annual output of Wi-Fi equipment will reach 33 million. Correct pronunciation [wai] [fai] The phonetic transcription is: "waifei" According to the famous American Webster's University dictionary and the French Robert dictionary, the phonetic symbol is [wifi], and the pronunciation is still "waifei". One of the outstanding advantages of WiFi is its wide radio coverage. The radio coverage based on Bluetooth technology is very small, with a radius of only about 50 feet? About 15 meters? And the radius of Wi-Fi can reach about 300 feet? About 100 meter? Needless to say, the office can be used in the whole building. Recently, Vivato Company introduced a new type of switch. It is reported that this product can make the current Wi-Fi wireless network reach 300 feet? Approaching 100 meter? The communication distance has expanded to 4 miles (about 6.5 kilometers). Secondly, although the wireless communication quality transmitted by Wi-Fi technology is not very good, the data security performance is worse than that of Bluetooth, and the transmission quality needs to be improved, but the transmission speed is very fast, reaching 54mbps, which meets the needs of personal and social informatization. Third, the threshold for manufacturers to enter this field is relatively low. Manufacturers only need to set up "hot spots" in crowded places such as airports, railway stations, coffee shops and libraries, and access the Internet to these places through high-speed lines. In this way, because the radio waves emitted by "hot spots" can reach the radius of tens of meters to 100 meters from the access point, users can surf the Internet at high speed as long as they enter this area with their laptops or PDA supporting wireless LAN. In other words, manufacturers do not have to spend money on network wiring access, thus saving a lot of costs. USB wireless network cards have different WIFI speeds according to the standards used by wireless network cards. Among them, the maximum value of IEEE802. 1 1b is1Mbps (some manufacturers have supporting equipment that can reach 22Mbps), IEEE802. 1 1a is 54Mbps, and IEEE 802./kloc. WIFI is a wireless network composed of AP (access point) and wireless network card. AP is generally called a bridge or access point, as a bridge between traditional wired LAN and wireless LAN. Therefore, any PC equipped with wireless network card can share the resources of wired local area network or even wide area network through AP, and its working principle is equivalent to a HUB with a built-in wireless transmitter or router, while the wireless network card is a client device responsible for receiving signals transmitted by AP. Wireless b/g indicates the model of network card, which can be divided into 802. 1 1a, 802.1/b, 802.1g according to its speed and technology. When it comes to wireless networks, everyone has a specious feeling. Is wireless a simple connection between two computers? Don't! This is the concept of wireless in the last century. The new generation of wireless network will establish people's brand-new feeling of wireless local area network, without wiring and relatively free to use. Demand determines the development of the market. IT is rare to see any IT technology or product with such a rapid growth momentum. It is no longer a dream to surf the internet anytime and anywhere without any constraints. Among them, WiFi plays a vital role. Wi-Fi stands for "wireless fidelity" and refers to a subset of IEEE 802. 11b that is fully compatible with the 802.1standard. It adopts open 2.4GHz direct sequence spread spectrum, and the maximum data transmission rate is 1 12Mbps. The transmission rate can also be adjusted to 5 according to the signal strength. The maximum transmission range of wireless communication is 300 meters outdoors and 100 meters indoors, which is the most used transmission protocol at present. Compared with wired network, it has many advantages: