Of these contenders, microwave has better prospects and has garnered most interest and developments from major manufacturers. There are now three main standards competing for market share worldwide: Bluetooth, 802.11, and HIPERLAN. Here's an overview of what each contender brings to the market.

Most of these wireless technologies use the 2.4 Ghz (1 gigahertz = 1 billion hertz) band. Why? This frequency band, from 2.4 to 2.4835 Ghz, is allocated by international agreement for use by industrial/scientific/medical low-power radio devices. Hence, it is open and does not require license, unlike other commercial frequency bands where licensing can cost several thousands or even millions of dollars. Note: ordinary FM radio band is from 88 Mhz to 108 Mhz (1 megahertz = 1 million hertz).

Named after a 10th century Norwegian king, this technology was developed by Ericsson in 1994 and standardized in 1999 with support from IBM, Intel, Nokia and Toshiba under the Bluetooth Special Interest Group (SIG). It supports synchronous connection oriented (SCO) link for voice and asynchronous connectionless (AC) link for data. It operates in the 2.4 Ghz ISM band using frequency hopping spread spectrum (FHSS) to minimize interference. It can attain data rates of 1 Mbps (million bits per second) using continuous variable slope delta (CVSD) modulation. Working ranges are 10 meters for a 1-milliWatt radio transmitter up to 100 meters for a 100-milliWatt radio transmitter. It connects by using very small networks or piconets, consisting of a master and up to 7 slave units, which are in turn connected to several other piconets.
The BLUETOOTH SIG ensures compatibility of devices from several manufacturers.

Named after the working committee assigned to prepare the standard, this technology was developed by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 Wireless Local Area Network Standards Working Group. It was standardized in 1997 (2.4 Ghz, 2Mbps) and further developments resulted to the 802.11b standard in 1999. It is primarily designed for data packets and uses direct sequence spread spectrum (DSSS) to minimize interference within the 2.4 Ghz ISM band . It can attain data rates of up to 11 Mbps, almost similar to wired Ethernet LAN, using complementary code keying modulation (CCK). In adverse conditions, data rates are reduced to 2 Mbps or 1 Mbps to ensure that data will go through. Working ranges are 25 meters at 11 Mbps indoors and up to 90 meters at 1 Mbps. A recent standard (802.11g) promises to deliver up to 54 Mbps using the same 2.4 Ghz band.
The Wireless Ethernet Compatibility Alliance (WECA) is working to ensure compatibility of devices from all manufacturers.

Due to the expected increased use of the 2.4 Ghz band, telecommunication authorities around the world agreed to allocate another license-free block of frequencies from 5.15 to 5.35 Ghz. Further, European authorities allocated another block from 5.470 to 5.725 Ghz, while US authorities allocated a block from 5.725 to 5.825 Ghz for this.

Part of the initiative of the IEEE in 1990 was a technology designed for the 5 Ghz frequency band. It was ratified as a standard in 1999. It uses orthogonal frequency division multiplexing (OFDM) to attain data rates of 54 Mbps, almost 5 times the rate of the other WiFi standard, but at a shorter range of around 20 meters.

The European Telecommunications Standards Institute (ETSI) developed a standard called High performance Radio LAN in 1997. This technology is designed to handle packetized data and act as an extension of an existing wired local area network. Current development is focused on HIPERLAN2 which also uses orthogonal frequency division multiplexing (OFDM) to attain data rates of 54 Mbps. Similar to the 802.11a standard, it uses direct sequence spread spectrum (DSSS) transmissions to minimize interference. Working ranges are 30 meters indoors and 150 meters outdoors. To allow operation in the European environment where there are other users of the 5 Ghz band aside from HIPERLAN, an automatic frequency allocation and a transmission power control feature is included to minimize interference with existing users.
The HIPERLAN2 Global Forum certifies compatibility of equipment from different manufacturers.

Due to the easy availability of wireless LAN equipment, some innovative tinkerers have found ways to expand its use into areas previously not though of. For example, in Hawaii, where phonelines to outlying areas are few and far between, these innovators have found ways to send their wireless signals as far as 5 to 10 kilometers. In California, the hotbed of electronics and computer developments, a few entrepreneurs have made trials offering wireless LAN connection over 10 to 15 kilometers in a development/suburban environment. In Australia, where the nearest neighbor in rural areas may be several kilometers away, there have been enterprising individuals who modified their wireless LAN equipment to send and receive signals from as far as 25 kilometers away.