The USRobotics 56K USB Hardware FaxModem delivers the performance and reliability you expect from USRobotics in a compact flexible form factor. This controller-based modem integrates powerful communications processing functions into the modem itself for assured performance without sapping your computer s processing power. It is also broadly compatible across major operating systems including Linux Windows and Macintosh. Quick Connect reduces your connection time to get you online quicker and V.PCM Upstream provides 50% greater upload speeds perfect for sending e-mail messages with large attachments. Also supports USRobotics Modem on Hold Application to screen incoming voice calls while online and to answer calls without losing your internet connection no second phone line is needed!