4,8,12,16 FXS/FXO analog ports PCI card Asterisk, Trixbox, Elastix Detecttion of busy tone, DTMF, FSK Adjustable line gain 4,8,12,16 FXS/FXO analog ports PCI card Asterisk, Trixbox, Elastix Detecttion of busy tone, DTMF, FSK Adjustable line gain Applications: 1, PBX/IVR Services2, VoIP Services3, VoIP Gateways4, FAX Server, FAX On Demand5, Voice Mail Services6, Call Centers7, Prepaid Calling Card ...