Dynex DX-NRUTER

Overview
OEM Gemtek WRTB-239GN (Gemtek WRTB-239GN_V01)

"ENG-X10-2001R RoHS" is silkscreened on the board in the FCC photos.

On the DD-WRT forums (high-res internal images and label shot)

Per the manual, the default network name of your router is "Dynex" followed by six digits that are unique to your router. The default SSID in actuality appears to be just Dynex (at least when reset via the reset button and the web configuration interface).

Links of Interest
User manual

Serial Pinouts
Pinout appears to be the same as the Belkin F5D8235-4 v1 (another Gemtek device). That pinout is below.

 J6 (GND) (RxD) (GND) --> Right side of board (VCC) (VCC) [TxD]

Pictures
User Images