4,8,12,16 FXS/FXO ports PCI/PCI-E card Asterisk, FreeSwitch, Elastix Detecttion of busy tone, DTMF, FSK ... Adjustable line gain PCI/PCI-E analog card for Freeswitch and Asterisksupport 4 to 16 FXS ... , CPU 800+MHZ3, RAM 128+MB4, Linux kernel 2.4.x or 2.6.xSize and Weight5, Size(L*W*H ...