... .323, MGCP, SIP protocol; 6. Echo cancellation, noise reduction; 7. Support Skype, UUcall, Alt, QQ, MSN, Talk, Yahoo, Sip Discount, X ... , WebCall, VOIP RAIDER, VoipWise Onet2phone; 8. Full duplex communication; 9. Support Skype speed-dialing function; 10. Key-in tone function. Skype USB Phone