The universal USB serial bus (the abbreviation of the English "Universal Serial Bus") appeared relatively long ago in terms of the development of computer technology - in January 1996, the initiative for developing 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 peripherals in Plug & Play mode, i.e. so that when you connect a device that has a USB connector, it is automatically recognized by the computer (provided that the appropriate drivers are installed). Also provided was the power of 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. That's when USB 1.0 connectors began to be installed on motherboards. After the release of the updated version 1.1 in 1998, in which errors were fixed and stability was improved, the USB connector became the norm for almost any computer.
The next stage is the appearance in 2000 of USB 2.0, which has made this standard the most common today. Its further development is gradually becoming USB 3.0, which has a large bandwidth and supports a large current strength compared to previous versions (which gives, for example, the ability to use external HDDs) while maintaining compatibility of the connectors.
Today, any computer has several USB ports (usually 3-4 on laptops, up to 12 on stationary ones). Their number can be increased by connecting special
splitters (USB hubs). Occupying only one USB port on a computer, it provides several ports at once.
Theoretically, up to 127 USB devices can be connected to one computer at a time. When connected, the hub is taken as a separate device (simply put, if you connect one hub and four devices, for the 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 a five-meter section you will need a separate kind of repeater with autonomous power supply).
There are two types of connectors and plugs. A type A USB connector is used when connecting various USB devices to desktops and laptops. Type B connectors have various
peripheral devices (such as printers, scanners, MFPs). There are two more options for the second type of connectors - 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 the computer, and their "hot" connection and disconnection is possible, since its design is designed for multiple connection-disconnection without disrupting the operation of both the device and the computer itself. All this makes the USB interface a truly unique means of data transfer, and, perhaps, no alternative is yet to be expected, at least in the near future.