USB is a serial bus, using four shielded wires for the USB 2.0 variant: two for power (VBUS and GND), and two for differential data signals (labelled as D+ and D− in pinouts). Non-Return-to-Zero Inverted (NRZI) encoding scheme is used for transferring data, with a sync field to synchronize the host and receiver clocks. D+ and D− signals are transmitted on a twisted pair, providing half-duplex data transfers for USB 2.0. Mini and micro connectors have their GND connections moved from pin #4 to pin #5, while their pin #4 serves as an ID pin for the On-The-Go host/client identification. COUNT 3
QSN1 What is USB? ANS1 a serial bus QSN2 What kind of wires does the USB 2.0 variant use? ANS2 four shielded wires QSN3 What are the four shielded wires in the USB 2.0 variant used for? ANS3 two for power (VBUS and GND), and two for differential data signals