Computer wireless Internet access devices have the following types:
1. Wireless network card
The function of a wireless NETWORK adapter is similar to that of an Ethernet network adapter. It functions as an interface to connect to a WIRELESS LAN. According to different interface types, wireless network cards can be divided into three types, namely, PCMCIA wireless network cards, PCI wireless network cards and USB wireless network cards.
The PCMCIA wireless card is hot swappable for laptops only, making mobile wireless access very easy.
PCI wireless network card is suitable for ordinary desktop computer use. In fact, THE PCI wireless card is just a common PCMCIA card inserted in the PCI adapter card.
USB wireless network card is suitable for notebook and desktop computers. It is hot swappable. If the network card has a wireless antenna, then USB port is a good choice.
2. Wireless Bridges
In terms of function, a wireless bridge can be used to connect two or more independent network segments, usually located in different buildings, separated by hundreds of meters to dozens of kilometers. So it can be widely used to connect different buildings. At the same time, according to different protocols, wireless bridge can be divided into 802.11b or 802.11g in 2.4GHz band and 802.11a in 5.8GHz band. Wireless Bridges work in three ways: point-to-point, point-to-multipoint, and relay connections. Especially suitable for long-distance communication in cities.
In the absence of tall obstacles (mountains or buildings), a pair of quick networking and field work temporary networking. The range of action depends on the environment and the antenna, now 7km point to point microwave interconnection. A pair of 27dbi directional antennas can achieve a 10km point-to-point microwave interconnection. The 12dbI directional antenna can achieve 2km point-to-point microwave interconnection. A pair of wireless bridge that only realizes the link layer function is a transparent bridge, and the device that has the network layer function such as routing and the directional antenna in the network 24dbi can realize the heterogeneous network interconnection in the real layer is called a wireless router and can also be used as a layer 3 bridge.
Wireless bridge is usually used for outdoor, mainly used to connect two networks, the use of wireless bridge can not only use one, must be more than two, and AP can be used alone. Wireless bridge has high power, long transmission distance (up to about 50km) and strong anti-interference ability. It does not have its own antenna, but is generally equipped with parabolic antenna to achieve long-distance point-to-point connection.
3. Wireless antenna
When the computer is far away from the wireless AP or other computers, as the signal weakens, or the transmission rate decreases significantly, or the communication between the AP or other computers can not be realized at all, at this time, we must use the wireless antenna to receive or send the signal gain (amplification).
There are many types of wireless antenna, but there are two common ones, one is indoor antenna, the advantage is convenient and flexible, the disadvantage is small gain, short transmission distance; One is an outdoor antenna. There are many types of outdoor antennas, one is directional antenna, the other is rod - shaped omnidirectional antenna. The advantage of the outdoor antenna is the long transmission distance. More suitable for long-distance transmission.