Wireless Networking Wi-Fi standards, explained
802.11a - Another development on the standard, both 802.11a and 802.11b were launched at the same time. 802.11a was aimed more at the business market as it had higher manufacturer costs over the 802.11b devices.
802.11a can support bandwidth up to 54 Mbps and uses a regulated range of 5 GHz compared to unregulated 2.4 GHz range of 802.11b. Because the two standards use different ranges they were incompatible with each other and subsequently this did cause confusion at the time. To use either standard you needed to ensure you used devices which supported the same standard.
Because 802.11a uses a higher frequency the signals can suffer problems going through walls, in some cases people have found a better signal is achieved connecting from above or below as these have lower resistance for the signal to the solid walls.
For: Faster maximum speed, capable of simultaneous connections, regulated frequency prevents signal interference from other radio technology devices.
Against: Higher cost and shorter signal ranges which can be more easily obstructed.
802.11g - In 2002 Wireless LAN devices which supported 802.11g started to be sold. Essentially this standards aim was to remove the confusion over the different standards and combine the best of both 802.11a and 802.11b into one standard. The result is 802.11g supports bandwidth up to 54 Mbps and uses the 2.4GHz frequency which gives it greater signal range. It is also backwards compatible with 802.11b standard products and vice versa.
For: Fastest maximum speed and support for simultaneous connections, good signal range.
Against: Can cost more than previous standards, minor interference possible due to the unregulated signal frequency.