1)24 VoIP channel or 12 VoIP channel; 2)1 or 2 E1; 3)With SIP protocol; 4)Signaling support: SS7, ISDN ... , meeting and Fax pass through etc.Product specification:* Provide 32 port FXS or FXO,can be hardware configured with plug ... in module base on customer requirement.* 24 VoIP channel or 12 VoIP channel* 1 or 2 E1/T1 Port* E1 ... 16, G.726-24, G.726-24, G.726-32, G.726-40* Fax support T.38 and pass through ...