US Robotics USR5686G. Modem speed: 56 Kbit/s, Interface: RS232 DB25. Certification: FCC IC UL CUL CE. Compatible operating systems: Server 2011, Windows 7 64 bit, Win 7, Server 2008 64 bit, Server 2008, Vista 64 bit, Vista, Server..., Minimum system requirements: Serial Port Phone Line Serial Cable. Dimensions (WxDxH): 6.5 x 3.75 x 1.3" (165.1 x 95.2 x 33 mm), Weight: 8.64 oz (244.9 g). Package dimensions (WxDxH): 9.5 x 5.71 x 2.6" (241.3 x 145 x 66 mm), Package weight: 26.4 oz (748.4 g)