Product Characteristics and Working Environment ?Compliant to USB 1.1 and 2.0 full-speed device ?Compliant to USB Audio Device Class Specification Version 1.0 ?Compliant to USB HID Version 1.1 ?USB connector voltage: 4.5V ~ 5.25V DC ?PSTN voltage: 24V ~ 60 V DC ?Ambient temperature: 0 ~ 55 C ?Humidity: 10% ~ 90% ?Operating system: Windows2000/XP/2003 ?SKYPE software requirement: SKYPE version 2.0 or above ?System with USB-ATAII installed ?No additional device drivers are required as all device drivers are all Windows built-in.