PC-to-PC and PC-to-phone operation Driver built-in, plug and play USB1.1 compatible, no need sound card No external power required Complies with H.323, MGCP, SIP protocol Caller ID function of VoIP calls 199 incoming call and 199 dialed number With LCD and LED show Echo cancellation, noise reduction Full duplex communication Application support:Netmeeting /Messenger, Mediaring, Net2phone, Dialpad Customized hand phone casing designs available Key-in tone function