... DTMF, FSK Adjustable line gain PCI/PCI-E analog card for Freeswitch and Asterisksupport 4 to 16 FXS/FXO ... On Demand5, Voice Mail Services6, Call Centers7, Prepaid Calling Card System8, Callback Service9, Traditional Calls/VoIP Calls Conference Hardware ... 800+MHZ3, RAM 128+MB4, Linux kernel 2.4.x or 2.6.xSize and Weight5, Size(L*W ... 90% Non-condensing4, Voltage: 5V/12V5, Power Dissipation Mas: 2.65w/10.8w