usb call recorder 1support FSK and DTMF single 2giving calling recorder system free 3support windows 2000,XP,vista usb call recorderProduct Introduction:The 2 lines recorder box ... by SKYLINE Co.,LTD,with FSK and DTMF.And the recorder support compressed format,just like 64kbs,8kbs.It is benefit ... AGC algorithm processor, reach perfect volume balance anywhere. 2 line USB recorder box/usb call recorder