[Thanks to the Wireless Answer guy for this info]

Can you mix older (2Mbps) and newer (11Mbps) 802.11 products?  The answer (as it typically is with this stuff) is that it depends.

Most vendor 802.11 products are compatible, if the manufacturers implemented them correctly.  However, the original 802.11 spec was interpreted by some vendors differently than others, so interoperability isn't guaranteed.  The 802.11 spec also doesn't cover some common functions.  For example, although reassociation is specified in 802.11, the mechanism that allows AP-to-AP coordination to handle roaming is not specified.

One of the biggest reasons WECA was formed was to ensure that all vendors implemented 802.11b (the newer 11Mbps standard) in the same way.  Those vendors that implemented an 802.11 function in a non-standard fashion will either have no function with 802.11b, or some functionality may be lost (like WEP, or PowerSave).

The major change in 802.11 vs. 802.11b is the data rate. If an 802.11b vendor builds an AP that allows the basic rates to be only 5.5 or 11Mbps, then legacy 802.11 systems will fail to connect. Most AP vendors have a configuration item to let you set the default rates, so you should be able to get 2Mbps and 11Mbps products talking.

Bottom Line: if properly implemented on the 802.11 side, and properly configured on the 802.11b side, different 802.11 series products should be interoperable.