The first wireless LANs came into being in 1994. Then Wi-Fi cards were so expensive (about five times more than now) and this blocked its development. In 1997 the Institute of Electrical and Electronic Engineers worked out the 802.11 standard. However people forgot about it very soon because of low capacity. Only in 1999 they introduced the 802.11b standard which brought higher capacities. This standard's development was a milestone because the biggest world-famous producers became interested in this technology. For example Cisco Systems or 3COM. The next step in the evolution of Wi-Fi was the 802.11a standard creation. The 802.11a ought to be theoretically faster. Nevertheless it did not gain support because of high hardware's prices, incompatibility with the 802.11b standard and smaller range than the latter. In 2002, at trade fair "Comdex 2002", there were presented some devices which could work in the new 802.11g standard. In 2003 this standard gained approval of IEEE and appeared in most producers' offers. 802.11g joins the capacity which is comparable to "a" and has the range like the "b" one. On the other hand, the signal might be interfered by mobile phones, microwave ovens and sometimes the Bluetooth.