Enterasys WS-AP3705i

Overview
"8RNLAP01..2A1G" appears to be silkscreened on the board in the FCC photos.
 * Probable 20:B3:99 OUI (it's on the FCC label)

This device uses an Atheros SoC (probably AR9344) and an Atheros chip for the 5GHz radio.