Build-in mic. and speaker Independent sound chip to handle Softphone VoIP Voice Quailty Only one USB cable to handle both Mouse and Phone OLED display screen with keypad ( option ),/li> Dot matrix caller-ID Volume Control 800 DPI Optical sensor Auto detection (or manual switch) between Mouse and Phone. USB 1.1 Interface PnP. No external power/sound card required High quality for full duplex communication Handy, style, portable for notebook & PC Patent Pending