Wireless Networks
Conventional Ethernet networks require cables connected computers via hubs and switches. This has the effect of restricting the computer's mobility and requires that even portable computers be physically connected to a hub or switch to access the network. An alternative to cabled networking is wireless networking. The first wireless network was developed at the University of Hawaii in 1971 to link computers on four islands without using telephone wires. Wireless networking entered the realm of personal computing in the 1980s, with the advent to networking computers. However, it was only in the early 1990s that wireless networks started to gain momentum when CPU processing power became sufficient to manage data transmitted and received over wireless connections.
Wireless networks use network cards, called Wireless Network Adapters, that rely radio signals or infrared (IR) signals to transmit and receive data via a Wireless Access Point (WAP). The WAP uses has an RJ-45 port that can be attached to attach to a 10BASE-T or 10/100BASE-T Ethernet hub or switch and contains a radio transceiver, encryption, and communications software. It translates conventional Ethernet signals into wireless Ethernet signals it broadcasts to wireless network adapters on the network and performs the same role in reverse to transfer signals from wireless network adapters to the conventional Ethernet network. WAP devices come in many variations, with some providing the Cable Modem Router and Switch functions in addition to the wireless connectivity.
Note: Access points are not necessary for direct peer-to-peer networking, which is called ad hoc mode, but they are required for a shared Internet connection or a connection with another network. When access points are used, the network is operating in the infrastructure mode.