50 FXS + 2 FXO Ports SIP / H.323 version 4Audio codecs - G.711 (a-law/µ-law) (64 kbps) - G.729 (8kbps) - G.723.1 (5.3/6.4 kbps) - Clear-mode GSM (Optional) - FAX Support - up to G3 FAX, using T.38 Modem Support - up to V.90, using G.711 Up to 8 VoIP channel analog: - 25 ports via RJ-21 connector- 2 FXO ports on RJ-45 connectors-600R, 900R or CTR-21 line impedanceLAN interfaces: - 2 RJ-45s, 10 BaseT / 100 Base TX, full / half duplex