OpenVox A400P, 4 FXS/FXO ports analog PCI card
FXS-200 is a dual-channel module with an FXO channel and one FXS channel with failover capability. When the PBX fails, the line of the Public Switched Telephone Network (PSTN) connected to FXO will automatically switch to the analog phone connected to FXS.
FXO100 cards from the A400 / A800 / A1200 series