EnGenius ESR6650

The device is an ESR-9753 with a USB port. Additionally, the FCC test report lists the ERB9250, ECB9300, Rosewill RNX-N4-3G, and HIFULL OBA-6800 as being identical models.

The device is on the DD-WRT supported devices table.. and is listed as having 4MB Flash and 32MB RAM.

Specs
Platform Serial Num. = ? FCC ID = U2M-SR97908005 Industry Canada ID = ? CPU Type = Ralink RT3050 MIPS Rev = ? CPU Speed = 320 MHz Bus = ? Flash Type = ? Flash Chip = Macronix MX29LV320CTTC-70G Flash Size = 4 MB Max Firmware Size = ? RAM Size = 32 MB RAM Chip = ? nvram Size = ? ETH chip1 = Ralink RT3050 Switch = Ralink RT3050 Port-based vlan = ? 802.1q vlan = ? Ethernet Port Count = 1-10/100-WAN 2-10/100-LAN Wired Standard = IEEE 802.3/3u Ethernet interface OUI = none specified boot_wait = ? bootloader = ? Flash Card Socket/Type = ? SD/MMC Mod Support = ? Expansion IF types = ? PoE = ? Power = 12 VDC, 1.25 A Connector type/size = Barrel plug LEDs/Color = Blue Size = ? USB = 1x USB 2.0 Serial Port = Yes JTAG Port = ? Supported by TJTAG/Version = ? Supported by dd-wrt as of = ESR-6650 v24 SP2 - build 12962 - 20090923 dd-wrt K2.4 Support = ? dd-wrt K2.6 Support = ? Special Features = 3G capable Radio Wireless Radio = Ralink RT3050 WLAN DSP processor = Ralink RT3050 Wireless interface OUI = none specified Antenna Connector Type = 2dBi, RP-SMA MIMO status = 1x1:1 Wireless Standard = IEEE 802.11b/g/n 802.11n = up to 150 Mbps 802.11g = 6, 9, 12, 18, 24, 36, 48, 54 Mbps 802.11b = 1, 2, 5.5, 11 Mbps WiFi Operating Frequency = 2.4~2.484 GHz Channel Bandwidth = (Auto, 20 MHz, 40 MHz) Radio cor_rev = ? Radio Capabilities = ? Other Default IP address = 192.168.0.1 Default login user = admin Default login password = admin Default SSID = ? OEM = ? 3rd Party Firmware Support = ?

Links of Interest

 * Datasheet

Pictures
FCCID U2M-SR97908005