Description: Support Skype， Ariton， UUCALL，QQ，YAHOOO，Messenger，Freecall， Siphone， X-PRO， Eyebeam r and many other VoIP platforms Adjustable Volume size Call mute function Call hold feature Compatible with USB1.1 and USB2.0 interface Without a sound card， the need of an external power supply Compatible with H.323， MGCP， SIP protocol Elimination of ECHO effectively， reduces noise Supports Skype speed-dial Support for PC-to-PC and PC-to-phone calls Specifications: Interface: USB1.1 and USB2.0 Type A USB connector Working voltage: 4V-5.25V DC Ambient temperature: -10~+40 c Relative humidity: 10%~95% Ambient noise: less than 60dB (a) System configuration requirements: MMX 300MHz Pentium or above， 128m or above， with a USB interface Microsoft Windows 2000\/XP operating system 56k or broadband modem Package included: 1 X USB Skype phone