U.S. Robotics USR5637 56K USB Controller Dial-Up External Fax Modem with Voice Controller-based modem integrates powerful communications processing functions into the modem itself, for assured performance without sapping processing power. Windows Server 2012 R2/Win 10 /Win 10 64 bit/Server 2012/Win 8/Server 2011/Win 7/Server 2008/Vista/Server 2003/XP/2000 Mac 10.4-10.12 Linux 2.4.20 kernel or higher (Unimodem TSP/TAPI compliant) Intel Pentium III 600 MHz or equivalent, 128 MB RAM, 5 MB hard drive space