US Robotics USR025630G. Modem speed: 56 Kbit/s, Interface: RJ-11, RS232/V.24. Minimum system requirements: RS232, Minimum processor: 486DX, Pentium. Operating temperature range (T-T): 0 - 50 °C, Operating relative humidity range: 20 - 80 %, Storage temperature range (T-T): -20 - 70 °C. Power supply type: AC. Dimensions (WxDxH): 152.4 x 114.3 x 34.9 mm