Types of USB connectors – the main differences and features
Currently, there are several types of USB connectors (Universal Serial Bus – Universal Serial Bus), which come in three versions – USB v1.1, USB v2.0 and USB v3.0. Version v1.1 is almost never used due to the too low data transfer rate (12 Mbps), therefore it is used only for compatibility. The second version of USB 2.0 now dominates the market. Most modern devices support this version, which provides a data transfer rate of 480 Mb / s, which is equivalent to a copy speed of 48 MB / s. However, due to imperfect implementation and design features, in practice, the real speed rarely exceeds 30-33 MB / s. Many hard drives are capable of reading information at a speed of 3-4 times more. The USB v2.0 connector is a bottleneck that slows down the work of modern drives. At the same time, for mice, keyboards andsome other devices, this does not matter much. The third version of USB v3.0 is marked in blue, which indicates belonging to the latest generation. The bandwidth of the third version of USB provides a speed of 5 Gb / s, which is equivalent to 500 MB / s. Given the fact that modern hard drives have a speed of 150-170 MB / s, the third version of USB has a large margin of data transfer speed.
Structurally, USB 1.1 and 2.0 are fully compatible with each other. If one of the connected parties supports version v1.1, then the data exchange will occur at a reduced speed, and the operating system will display a message: “The device can work faster,” which means that the computer uses a fast USB 2.0 port, and The plug-in device version 1.1 is slow. Compatibility between USB 2.0 and 3.0 is slightly different. Any USB v2.0 device can be connected to the third version port, indicated in blue. But the reverse connection (with the exception of type A) is impossible. Modern cables and USB v3.0 devices have additional contacts that allow you to increase the speed of the interface.
Any USB connector is powered by a voltage of 5 V and current up to 0.5 A, and for USB version 3.0 – 0.9 A. In practice, this means that the maximum power of the connected device does not exceed 2.5 W or 4.5 W for USB 3.0. For this reason, connecting low-power and portable devices (telephones, players, flash drives, memory cards) will not cause problems, and large-sized and massive equipment is powered by an external network.
USB v2.0 and USB v3.0 connectors are also classified by type (type A and type B) and size (MiniUSB and MicroUSB).
USB 2.0 Type A
The USB Type A connector is most widely used and is the most recognizable among existing ones. Most devices (mice, keyboards, flash drives, cameras, and many others) are equipped with USB Type A, which was developed back in the 90s. The main advantage of this port is its reliability, which allows it to withstand a large number of connections and not lose integrity. Although the cross section of the connector is rectangular, it provides protection against improper connection, so it cannot be plugged in. However, it has rather large dimensions, therefore it is not suitable for portable devices, which as a result led to the creation of smaller modifications.
USB 2.0 Type A
USB 2.0 Type B
The USB Type B connector is less popular. All Type B modifications, including Mini and Micro, are square or trapezoidal. The traditional full-size type B is the only type that has a square section. Due to its relatively large size, it is used in various peripheral and large-sized stationary devices (scanners, printers, and sometimes ADSL modems). Typically, manufacturers of printers or multifunction devices rarely bundle their products with such a cable, so the buyer has to purchase it separately.
USB 2.0 Type B
Mini USB 2.0 Type B
The reason for the appearance of tiny Mini USB Type B connectors was the abundance in the market of miniature devices. And the real mass character was ensured by the appearance of portable hard drives. Unlike large connectors with 4 pins, the Mini USB Type B has five pins, however, one of them is not involved. Unfortunately, miniaturization negatively impacted reliability. During operation, after some time, the Mini USB connector begins to loosen, although it does not drop out of the port. At present, it is still actively used in portable hard drives, players, card readers and other compact equipment. The second modification of Mini USB Type A is almost never used. Mini USB is gradually replacing a more advanced modification of Micro USB.
Mini USB 2.0 Type B
Micro USB 2.0 Type B
The Micro USB Type B connector is a modified version of the previous Mini USB Type B and has a very miniature size, which allows manufacturers to use it in modern technology with a small thickness.