US Robotics USR5686F-VAR-20. Modem speed: 56 Kbit/s, Interface: RS-232/V.24-DB25. Compliance industry standards: V.92/V.90. Minimum system requirements: IBM PC 56K line RS-232 cable V.90 56K ITU/V.92 56K ITU, Minimum processor: 500+ MHz, Minimum RAM: 128 MB. 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: 9V, 1A