As a mouse: 1.5m USB cable (USB 1.1) 800 dpi optical sentor As a Hi-Fi Speaker: Crystal clear sound quality 48 KHz sampling rate Supplied earphone to protect your privacy. As a VoIP Phone: Auto detection between mouse and VoIP phone Seamlessly integrated with Skype, VoipButser, VoipStunt, VoIPCheap, VoipDiscount, SparVoip, Internetcalls, poivY, WebCallDirect, VoipCheapCom, FreeCall and NetAppel. Seamlessly integrated with X-TAPI Lite/Pro and BeyondTel's SIP Softphone Monochrome 128*64 pixel LCD with backlight. Supports all kinds of languages VoIP Contact List, Call List, Call history, time, and caller ID display on LCD screen Hands-free speakerphone function Various chord music ring tones catering to different tastes. Fully functional keypad and LCD screen enables you to make/receive calls without using keyboard and mouse. Rings loudly on an incoming call. Acoustically isolated earpiece and microphone to eliminate echo. Full-duplex communication with crystal clear voice.