DealExtreme 92141

Overview
aka China-brand WR3G01

"XDX-RN502J V5.0" is silkscreened on the board. This is similar to text on the Winstars WS-WR511N1 and they likely share the same manufacturer (if not Winstars).

Links of Interest
The below links are for XDX-RN502J V2.0 (China XDX-RN502J V2.0)
 * On the DD-WRT forums
 * On the OpenWrt wiki
 * On the OpenWrt wiki again as the "Widemac SL-R720X"
 * On the OpenWrt forums