product description cisco ip phone 7821 voip phone product type voip phone main features multiple voip protocol support integrated ethernet switch voip protocols sip srtp voice codecs g722 g729ab g711u g711a ilbc lines supported 2 lines speakerphone yes digital duplex call services voice mail caller id call waiting call forwarding call transfer call hold message waiting capability display lcd display monochrome yes network ports qty 2 x ethern