Specification: 1.PnP USB interface,compatible with USB 1.1 and 2.0 2.16 bit sound card inside,the PC can without Sound Card 3.Built-in DTMF dialing 4.Incoming call ringing,easy for answering 5.The powered via the USB port with not need for a power adaptor 6.Compact appearance design suitable for notebook 7.Applicable for wide and compatible multi calling platforms 8.Choosing proper platform to communicate between two USB IP phones 9.Review incoming and outgoing call 10.Supports Skype etc software 11.The LCD can display Year/Month/Day/Time