... Three-way conference/Call waiting fun Important: It can store two SIP accounts, press 1# key, choose the first SIP ... the second SIP Account to call...2, the two SIP Account from two ITSP, the first SIP Account call to USA ... calls;7,DND function;8,Roaming function;9,Check local number;10,Speed dial function;11,Display date, time, and ... in a semiduplex way to ensure the talking quality; Two Line VoIP Phone