The Universal Serial Bus USB (an abbreviation of the English "Universal Serial Bus") appeared relatively long ago in terms of the development of computer technology - in January 1996. The initiative to develop the standard belongs to well-known manufacturers of computer equipment (Compaq, DEC, IBM, Intel, NEC, Northen Telecom).
The main task that the developers set themselves was to enable their users to work with peripheral devices in the Plug&Play mode, i.e. so that when you connect a device with a USB connector, it will be automatically recognized by the computer (provided that the appropriate drivers are installed). It was also planned to power low-power devices directly from the bus itself.
At the same time, the bus speed should have been quite sufficient for almost any peripheral devices. It was then that USB 1.0 connectors began to be installed on motherboards. After the release in 1998 of the updated version 1.1, which fixed bugs and improved stability, the USB connectorhas become the norm for almost any computer.
The next stage is the appearance in 2000 of USB 2.0, which made this standard the most common today. Its further development is gradually becoming USB 3.0, which has more bandwidth and supports more current than previous versions (which makes it possible to use external HDDs, for example) while maintaining connector compatibility.
Today, any computer has several USB ports (usually 3-4 on laptops, up to 12 on desktops). Their number can be increased by connecting special splitters (USB hubs). Taking up only one USB port on your computer, it provides multiple ports at once.
Theoretically, up to 127 USB devices can be connected to one computer at the same time. When connected, the hub is taken as a separate device (simply speaking, if you connect one hub and four devices, for a USB host, the number of connected devices will be five). As for the maximum length of the USB cable, it is 5 meters. If you need more, you can’t do without a special extension cord (for each such five-meter section, you will need a separate kind of repeater that has autonomous power).
Connectors and plugs are of two types. The Type "A" USB connector is used when connecting various USB devices to desktop computers and laptops. Type "B" connectors have various peripherals(e.g. printers, scanners, MFPs). There are two more connectors of the second type - a mini-USB connector (used to connect devices such as digital cameras, PDAs or cell phones) and a micro-USB connector (even more compact, usually used when connecting cell phones).
Using the USB standard allows you to connect almost all modern peripheral devices to a computer, and their "hot" connection and disconnection is possible, since its design is designed for repeated connection and disconnection without disrupting the performance of both the device and the computer itself. All this makes the USB interface a truly unique means of data transfer, and, perhaps, there are no alternatives yet, at least not in the near future.
