Foundry Networks AP150

"USI", "8501-6000[.]-01", and "REV:3.1" is silkscreened on the board.
 * OEM: USI (OUI: Brocade Communications Systems, Inc.)

It seems this board may be somewhat similar to other USI AR5312 boards
 * (for example, the Proxim ORiNOCO AP-4000).