Wireless networks have undergone a few changes in recent years with a least three existing standards now available, these being 802.11a, 802.11b and 802.11g. Unless you are operating in a business environment you are unlikely to come across 802.11a, which operates at a frequency of 5.0GHz and has a maximum data transmission rate of 11.0 mbps (megabits per second). If you are using a wireless network in your home it is likely to be either the 802.11b standard (2.4GHz frequency and 11.0 mbps transmission rate) or 802.11g if you've purchased it in the last 2-3 years (2.4GHz frequency and 54 mbps transmission rate). While a "g" standard network in the home serves most needs, it has difficulty streaming high-quality video, a multimedia application that is likely to become standard within the next five years. To address this (and for many other reasons) a new standard, 802.11n, is being formulated that will allow data streaming at up to 270 mbps, or 5-times the current "g" standard.
This new standard is currently at draft 2.0 and a vote on the draft is expected in January 2007. However, it is widely believed that a third draft will appear later in 2007 and that the standard will not be ratified until early 2008. However, in the meantime, a number of wireless network equipment manufacturers have released what are known as "Pre-n" devices - both routers and adapters - that conform to the current standard draft, but which will most probably not conform to the final ratified standard. While the manufacturers may make claims that these will give you greater performance to existing ratified standards, you should purchase such units with caution. It is possible that these units will not conform with the final standard (though most manufacturers claim they will release firmware updates to address this, there are no guarantees that they will) and that they will most probably not be compatible with equipment from other manufacturers (only Wi-Fi Alliance certified equipment is guaranteed to work with other certified equipment from other manufacturers). A recent review of pre-n equipment by PC World magazine found that many of the pre-n routers and network cards did not offer the benefits of the marketing hype and they suggested that you should look to MIMO-based "g" standard units for best performance and leave the pre-n kit until the standard is ratified.