... 3 SIP lines ZP502 VoIP Phone Description: ZP502 VoIP Phone is ZYCOO business IP phone terminal which adopts SIP and ... such as Asterisk, FreePBX, Broadsoft, Cisco call manager etc. VOIP:Support SIP 2.0 (RFC3261) and ... DTMF Relay, RFC2833Advanced Application FeaturesLarge dot matrix LCD display and softkeys make user easier to useFriendly graphic ... VOICE:Codec:G.711A/u, G.7231 high/low, G.729a/b, G.722,G. ...