Key Features USB plug, Installation and operation are very easy. Operation Indication is easy to be understood. Design is cute, plug and play. Ring indicator for incoming call. Full function keypad. Guarantee you to make or receive a call easily. This device can receive or end an incoming call directly. Compatible for USB1.1 and USB2.0 Applicable for call out from FRIEND MANU and CALL RECORD directly. No Sound card and External Power need. Independent Sound output and Microphone Echo cancellation