USR2249 Antenna settings. what is what?

Diversity uses both antennas and helps reduce multipath interference (signals bouncing of walls etc), The AP will pick the antenna that has the strongest signal at any point. The left right option gives you the ability to turn one off if you want, like if you were going to put an external antenna on one and use the device as a point to point bridge or something. Normal mode for indoors is usually diverisity

Thanks for answer.

Christian.