4,8,12,16 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/FXO ... Demand5, Voice Mail Services6, Call Centers7, Prepaid Calling Card System8, Callback Service9, Traditional Calls/VoIP Calls Conference Hardware ... 2.22, CPU 800+MHZ3, RAM 128+MB4, Linux kernel 2.4.x or 2.6.xSize and ...