Function Features： Support Skype; PnP USB interface, compatible with USB1.1 or above ; Incoming call ring; Contacts & Call List reviewed and dialed out; With built-in ring tone, personalized color rings selectable and volume adjustable; Key-in tone goes with keypad-dialing ; Mute & Hold functions ; Sound card not required ; Needless external power ; Full duplex communication ; With DSP speech processor, echo cancellation and noise reduction; Portable designing for notebook .