IP PBX With unlimited user,20 line, 4FXO 1)support 24 current calling lines 2) 4 sip accounts Based on AsteriskEmbeded IP PBXWith 4FXO or 4FXSNo limited in user license, sip trunk, conference user 20 concurrent callsVoice codec: G711U, G 711A, G723.1, G729, G726 and can transfer codec. Vdeo codec: H.264, H.261, H.263, H.263+