USB audio dongle with PCM2912 - Pavouk Green LED signalize playing and red recording. Button is for mute of microphone. Circuit diagram is practically identical to the schematics in a datasheet. USB part of chip includes three endpoints. One control endpoint and two audio streaming interfaces for input and output. USB pinout, wiring and how it works! - Electroschematics The USB is a plug-and-play interface between the PC and the peripherals. The main advantage of USB is that the device can be plugged in or plugged out without the need of restarting the PC 🙂 USB is the short form of Universal Serial Bus, a standard port that helps to connect computer peripherals like scanner, printer, digital camera, flash drive and more to the Computer.