1.PC-to-PC and PC-to-phone operation;2.Driver built-in, plug and play;3.USB1.1 compatible;4.No need sound card;5.No external power required;6.Complies with H.323, MGCP, SIP protocol;7.Echo cancellation, noise reduction;8.Application support: Skype, Netmeeting /Messenger, Sjphone, Mediaring, Net2phone, Dialpad, Etalk, X-PRO, X-PRO Vonage, Firefly, Eyebeam and so on;9.Full duplex communication;10.Support Skype speed-dialing function;11.Key-in tone function.