The 802.11g spec was drafted in Nov of 2001.  802.11g operates on the same frequencies as 802.11b and is backwards compatible!  The planned common implementation of consumer 802.11g devices operate at a maximum of 22Mbps but can communicate at up to 54Mbps.   802.11g is sometimes called 'Turbo Mode' on some 802.11b cards.

Like 802.11b, 802.11g is subject to the same interference and security issues.  It operates at 2.4Ghz and may cause problems with 2.4Ghz cordless telephones.

 

When a 802.11g product communicates with an 11Mbps 802.11b product, it drops down to 11Mbps or less depending on signal strength.  In other words, if you purchase an 802.11g product for use with an 802.11b access point, expect only 11Mbps.