USB pinout

USB pinout is information showing the purpose of each connector pin of the corresponding interface. The universal serial bus, developed by Microsoft and Compac in the distant 1996, has gradually supplanted many protocols from computer technology, for example, GamePort, COM and LPT.In some places, USB is already being used instead of PS / 2.

Universal Serial Bus

Considered to be truly universal, consists of only two wires. A pair of contacts provides power to the connected devices. Thanks to this feature, it becomes possible to charge smartphones from personal computers, which is much more convenient than constantly carrying( say, visiting) a bunch of adapters. The system unit is equipped with a large number of ports to simultaneously communicate with multiple devices. The most powerful ones detect their own power supply, others take energy directly through the wire.

For this reason, with the growth of the standard generation number, the current limit transmitted via the interface also increases:

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  1. Current consumption of devices via USB 0 to 0.5 A.
  2. Current consumption of devices via USB 0 to 0.9 A.
  3. Current consumption of devices via USBBC 2 up to 1.5 A.
  4. Current consumption of devices through USB Type C up to 3 A.
  5. Current consumption of devices through USB-PD up to 5 A.

Universal pinout

To make it clearer, at a supply voltage of 20 V for USB-PD atThis current can transmit 100 watts of power. This is quite enough to connect an inkjet printer. By the way, if you look at essays on the net, there are no specific numbers. Meanwhile, the determination of the power consumption is extremely simple. Tips for those who want to perform the task with their own hands:

  • An extension cord is made, with a power cord without common insulation, but with private insulation of each core.
  • Clamps any core with current tongs.
  • The printer is turned on.
  • The readings are marked.

Then it is necessary to multiply the current by 220 V. The accuracy of digital indicators usually allows you to detect the proportion of amperes, which is suitable for assessing whether 100 W is enough( current consumption 0.45 A) for our purposes. It is even easier to use a digital multimeter in the right mode. It is clear that you have to assemble a special stand. We are sure that the inkjet printer consumes much less than 100 watts.

When the perspective of the technology became clear( additionally, due to the lobbying interests of the interface by the developers), new versions began to appear. A standard port size with dimensions selected on the basis of strength requirements cannot be applied due to a mass of considerations. The authors have bothered to translate into Russian a picture from Wikipedia, and now readers will find out what the pinout of the USB plug looks like. In the outlet on the back of the system unit, the layout is mirrored.

The history of the development of

The interface is considered the joint brainchild of Edge Bhat from IBM and the USB Developer Forum. Before the first release of 1.0, the port has undergone quite a few revisions. Since 1994, seven companies have taken part:

  • Compac( computer and digital equipment).
  • DEC( closed today).
  • Intel( processors and other electronics).
  • Microsoft( no comments).
  • NEC( better known for DVD-drives).IBM
  • ( software and components manufacturer).
  • Nortel( founded by Alexander Bell, specializes in the communications segment).

Types of USB connectors

The goal was integration. Electronics manufacturers understood that the abundance of interface varieties confused the consumer, reducing the demand for products. In this sense, a competitive solution was to adopt a single interface, which saved most of the population from solving complex technical problems. Today, the USB mouse starts working in a split second after connecting without questions and notifications. For comparison, the analogue on PS / 2 becomes visible to the system only after a reboot. And the interface for COM mice has long faded into oblivion due to low data transfer rates.

Thus, the tire turned out to be universal and easy to understand. Although complex equipment still requires the installation of special drivers. However, the A4Tech X7 mouse with all macros performs common functions immediately. And only the use of special features makes it necessary to install the driver. In other words, the port’s capabilities are unique. Already the first release was supported at the level of the Windows 95 operating system of the second version and provided the user with two speeds:

  1. 1.5 Mbit / s was enough for pointers, joysticks and other manipulators.
  2. 12 Mbps allowed to connect external drives.

For comparison: the COM port provided 100 kbps. For technical reasons, advanced capabilities could not be reached.1.1 is considered the first widespread release. The only port through the splitters was able to support up to 127 devices simultaneously. The ambitions of the developers looked truly gigantic.

For hardware support by IBM, they began to produce special chips that motherboard manufacturers used as part of the product. The success of the interface was promoted by the success of Apple’s iMac computers. In April 2000, USB 2.0 specification was announced, where the maximum data transfer speed increased by 40 times compared with the first release. The port left full compatibility with previous versions and now already supported three bit rates.

In the second generation, the ability to power devices via the specified interface appeared, and the user became happy with the Plug-and-Play options( turn on and play), immediately renamed Plug-and-Pray( turn on and pray).The specification has evolved, through the On-The-Go protocol, it became possible to combine two digital devices without a host, in this role the system unit of a personal computer appeared. In 2000, the first flash drives appeared, which uniquely tied the hearts of users to a new interface. At that time, the medium contained as much as 8 MB of data.

The USB 3.0 interface of 2010 supports four( three inherited and one new SuperSpeed) speeds up to 4.8 Gbit / s( and USB 3.1 already up to 10 Gbit / s), leaving compatibility with the previous version. And although the old cables correspond in size, due to the technical features( considering the number of wires), transferring information at full speed would require the purchase of new ones. In the mentioned generation, the maximum current consumption of the connected devices turned out to be dramatically increased. At the same time, type C plugs and USB sockets were published. It is clear that it is easy to get confused in abundance.

A distinctive feature of connectors is the presence of a characteristic trident icon with arrows at the ends where the logo is placed.

Varieties of connectors

USB pinout is not the same for different port versions, the location of the contacts and the number varies. We met with types A and B( according to the picture).Type C includes:

  1. Four pairs of power contacts.
  2. Two pairs of old USB0 transfer protocols.
  3. Four SuperSpeed ​​high-speed data buses.
  4. Two pins of data transfer.
  5. Two configuration contacts.

Pinout with types A and B

We will now try to organize the voiced set of information. Until the third generation, there were two types A and B, each with three subspecies: ordinary, mini, and micro. Mini Now it is considered obsolete, but all are presented in the figures. Ordinary carry four contacts( from English - pin), others - on 5. Assignment is given in the table:

Normal Mini and micro
1 +5 V( wire red, orange) +5 V( wire red, orange)
2 Data -( white wire, gold) Data -( white wire, gold)
3 Data +( green wire) Data +( green wire)
4 Ground( black wire, blue) Device Role ID
5 - Ground( black wire), blue)

To understand the role of the device, we recall that mini and micro interfaces are used in the manufacture of digital gadgets and office equipment. On the system unit there are none. When two devices are connected, one becomes the host( dominant), then the contact is grounded, and the second - by the client( the contact hangs in the air).Most cell phones, iPads, are equipped with similar interfaces today. Through them, by the way, is recharging. We believe that people sometimes do not know about the possibilities of the On-The-Go option.

Connectors connectors

Type A connectors survived all generations without a change( except for the mini outdated), type B became slightly larger in size. Type B USB 2.0 plugs fit in new sockets, but not vice versa. Of course, electrical compatibility is maintained. USB 3.0 micro B began to consist of two slots. The number of contacts has changed, increased. The above is shown in the figure, and below is a table assigning contacts.

Assignment Connector Pin Micro-B USB 3.0
1 5 V supply
2 USB 2.0 Date -
3 USB 2.0 Date +
4 RoleId device
5 Earth Power
6 USB 3.0 transmission -
7 USB 3.0 Transfer +
8 Earth
9 USB 3.0 Admission -
10 USB 3.0 Receive +
No. Pin Assignment of USB 3.0 Connector
1 Power 5 V( Red Wire)
2 USB 2.0 Date -( White Wire)
3 USB 2.0 Date +( Green Wire)
4 Power Ground( Black Wire)
5 USB 3.0 Transfer -(wire blue)
6 USB 3.0 Transmit +( wire yellow)
7 Signal ground( colorWater is not defined)
8 USB 3.0 Admission -( violet wire)
9 USB 3.0 Admission +( orange wire)

new interface at the same time working on reception and transmission on the new standard and is backward compatible. Technically, it is possible to insert a micro connector in one of the interface slots in previous versions. The wiring of contacts 2 and 3 form a twisted pair, known for "enhanced" type B interface, where there are 2 more power contact power. All shown.

It remains to add that the power contacts are usually slightly longer than the data. This ensures the safety of information on removable media, where loss was often recorded before. This difficulty is still being taken into account in operating systems where the option of removing removable media is present. Lengthening the power contacts ensures their priority in switching on, even if the connector is physically skewed.

USB Type-C Connector

This connector holds 24 pins, the pinout of the USB plug is shown below, see figure in section.


No. Assignment of USB Type C connector
1 A1 Land( platinum wire)
3 A3 USB 3.0 Transmission Business Card
9 a9 usd usb 3.0 receptionDate +
19 A7 USB 2.0 Date -
20 A8 Data Transfer Band
21 А9 Power
22 A10 USB 3.0 Receive +
23 A11 USB 3.0 Receive -
24 A12 Ground

USB Type-C Connector

Despite the abundance of contacts, the size of USB 3.0 Type C connectors is modest, at the level of the mini subspecies. This interface is supported, starting with the operating systems Windows 8 and Android 6. On the system units of personal computers it is presented in small quantities, mostly intended for netbooks, smartphones and other mobile devices. Look at the location of the pins: thanks to this, the cord came out reversible. There is no longer any difference what side to plug the connector into the slot. This is convenient in the dark, because we often carry gadgets outside, where in the evening there is insufficient lighting.

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