... Full duplex hands-free speakerphone 2.Support 1 IAX2 & 3 SIP lines ZP502 VoIP Phone Description: ZP502 VoIP Phone is ZYCOO business IP ... as Asterisk, FreePBX, Broadsoft, Cisco call manager etc. VOIP:Support SIP 2.0 (RFC3261) and correlative RFCsSupport IAX2Supports 3 SIP lineSupport ... 100 records. VOICE:Codec:G.711A/u, G.7231 high/low, G.729a/b, G.722,G.726Echo cancellation: G.168 Compliance in LEC, ...