Feature: USB 2. 0 port; 16 bit sound card inside, the PC can without Sound Card; Support H. 323, SIP, MGCP etc lot of protocol; Support product serial write in; With HID (Human Interface Device) Feature; Plug & Play to Install USB Driver; No driver needed for Win98 SE/Win ME/ Win 2000/Win XP/ Mac OS/Mac OS X; With PID (Physical Interface Device) Feature; Implement 'Real-Time' verification; Compatible with Major PC's Internet Phone Application Software; Provides Ringer Generation for PC to PC Call Through Existing IP phone Applications: Optional ITSP Application Software With Credit for PC to Phone Connection; ALED to indicate Power and Linking Status; Adjustable volume for handset; Support E. 164 dialing rule; Record support; The powered via the USB port with no need for a power adaptor; It can support Skype, MSN, net2phone, etalk, Stanaphone, SJphone, X-Lite, X-PRO, Firefly, eyebeam, Baoshitong etc software.