What is USB? UNIVERSAL SERIAL BUS What does it do?It connects your laptop or PC to the peripheral devices attached to it.How does it communicate?You attach the device using a cable to PC and communication is initiated within a fraction of seconds. However, what looks easy on our end is a complicated process in the USB system. It may be single step in our stride to attach the device and start working but for the system it’s entirely a different picture. In that fraction of second after the device is attached, it initiates step by step process to make communication possible. It starts right from alerting the PC about the attachment, change in voltages at ports, then addressing the devices, gathering the information, loading the drivers and finally communication. Let’s understand each of these steps in detail to get a crystal clear picture about the working of USB.