Universal Serial Bus (USB) jacks and ports area unit tools that enable you to attach pc peripherals to your computers, keyboards, external laborious drives, or storage keys.
The numbers following the USB image merely correspond to the version of the USB customary involved, the 3.0 and 3.1 series being the foremost recent at the time these lines area unit written.
In addition to the colour of their connectors (version three.0 is sometimes blue), it's the speed of knowledge transfer that's the most distinction between these 2 standards.
Thus, the USB 2.0 standard, introduced in 2000, created it doable to ensure a transfer speed a lot of more than that of the previous standard: from one.5 MB per second to theoretical sixty MB! USB three.0, appeared in 2008, has increased this transfer rate by ten, reaching the theoretical rate of 625 MB per second!
Be careful, if backward compatibility is supported within the case of USB three.0 jacks (that is, your device with a USB three.0 port can work on your pc with USB a pair of.0 sockets), the speed of transfer can stay blocked to a pair of.0 standards...
USB standards. As early as 1995, the USB customary was developed for connecting a good style of devices.
The USB 1.0 customary offers 2 modes of communication:
12 Mb / s in high-speed mode.
1.5 Mb / s at low speed.
The USB 1.1 customary provides some clarifications to USB device makers however doesn't modification the bit rate.
The USB 2.0 customary provides hastens to 480 Mbit / s.
The USB 3.0 customary provides hastens to four.8 Gbps.
In the absence of a emblem the most effective thanks to confirm whether or not these area unit USB devices at low or high speed is to consult the merchandise documentation as long because the connectors area unit identical.
Compatibility between USB one.0, 1.1 and 2.0 devices is assured. However, employing a USB a pair of.0 device on a low-speed USB port (i.e. 1.0 or 1.1) can limit the bit rate to twelve Mbps. additionally, the package could show a message explaining that the flow are restricted.
There area unit 2 kinds of USB connectors:
The alleged blood group connectors, whose form is rectangular and customarily used for devices low in information measure (keyboard, mouse, webcam, etc.);
The alleged type B connectors, whose form is sq. and used primarily for high-speed devices (external laborious drives, etc.).
Description: USB blood group and kind B Connectors
1. Power + 5V (VBUS) 100mA most
2. Data (D-)
3. Data (D +)
4. Mass (GND)
USB bus operation
The USB design has the characteristic of providing power to the peripherals it connects, up to a most of fifteen W per device. It uses a cable consisting of 4 wires (the GND ground, the VBUS power provide and 2 knowledge wires known as D- and D +).
Description: the USB cable
The USB customary permits the chaining of devices, employing a bus or network topology. The devices will then either be connected one when the opposite, or branched.