... ,8,12,16 FXS/FXO ports PCI card Asterisk, FreeSwitch, Elastix Detecttion of busy tone ... FSK Adjustable line gain PCI/PCI-E analog card for Freeswitch and Asterisksupport 4 to 16 FXS ... , Voice Mail Services6, Call Centers7, Prepaid Calling Card System8, Callback Service9, Traditional Calls/VoIP Calls Conference ... C2, Temperature Storage: -35°C to 120°C3, Humidity: 10% to 90% Non-condensing4, Voltage: 5V/ ...