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In our age of computer technology, smartphones and gadgets, it is difficult to find a person who does not know what USB connectors are. Also, almost everyone understands words such as mini- and micro-USB connector. After all, we use such things almost every day, which is natural. Similar connectors are found on the charger and on all peripheral devices of the computer.

But what to do if the soldering has come off at the base, and there is no way to even understand what color and what contact was soldered to? This is where knowledge should be applied, and now let’s try to figure out which ones.

The wiring of such a plug, or, in other words, the pinout of a USB cable, inherently does not involve anything overly complicated. Once you get the sequence and colors figured out, anyone who can hold a soldering iron can do this kind of work.

But first you need to understand what a USB plug is.

What is a USB connector?

At its core, it is a connector with many capabilities, ranging from USB power to transmitting complex information data. This cable replaced the previously used options for connecting to a computer (PS/2 ports, etc.). Today it is used for all devices connected to a personal computer, be it a mouse, flash drives, printer, camera or modem, joystick or keyboard - USB cables have become truly universal.

There are three types of such connectors:

• 1.1 - its purpose is already outdated peripheral devices with the ability to transmit information at only one and a half megabits per second. Of course, after a little modification by the manufacturer, the transmission speed rose to 12 Mbit/s, but it still couldn’t stand the competition with higher-speed options. Of course, when Apple already had a connector that supported 400 Mbit/s. Now there are also such types, but there are very few of them, since faster USB wires, mini USB, and in general, USB speed occupies a special place in human life. Everyone is in a hurry somewhere, in a hurry to live, there are people who practically do not sleep, and therefore the faster the information is downloaded, the more preferable the connector is, right?
• 2.0. At the end of the last century, the second generation of such connectors was released. Here the manufacturer has already tried - the transmission speed has increased to almost 500 Mbit/sec. And it was intended mainly for complicated gadgets, like a digital video camera.
• 3.0 - this is really high technology. The maximum data transfer rate of 5 Gbit/s provided this USB connector with demand, which practically reduced the first and second versions to zero. In the third series, the number of wires has been increased to nine versus four. However, the connector itself has not been modified, and therefore you can still use the types of the first and second series with it.

Pinout designations

When looking at the pinout diagram, you need to understand all the symbols that are present on it. Usually indicated:

• Type of connector - it can be active (A) or passive (B). A connection between a printer, scanner, etc. is called passive. In general, a connector that only works to receive information. Through the active it is possible to receive and transmit data.
• The shape of the connector is “mother”, that is, a socket (F), and “male” is a plug (M).
• Connector sizes - regular, mini and micro.

For example, USB AM, that is, an active USB plug.

The wires should be arranged by color as follows (from left to right):

• The red wire is positive, constant voltage 5V. with a maximum current of 500 milliamps.
• White wire - data-
• Green wire - data+
• Black wire - this wire is common, ground, negative. There is no voltage on it.

But the mini and micro connector include 5 wires with this arrangement:

• The wires are red, white and green - arranged similarly to the first option.
• ID - this wire in connectors “B” is free. In “A” it must be connected to a black wire.

Sometimes the connector may contain a separate wire without insulation - this is the so-called “ground”, which is soldered to the body.

According to the presented diagrams, the external side is visible here. In order to solder the plug yourself, you need to take a mirror image of the picture, and as it probably became clear, the microUSB pinout is no more complicated than that of conventional USB connectors.

By the way, if the damaged parts of the cable are intended to be used only for charging mobile phones, it will be more convenient to look at the colors of the wires and solder only black and red. This connector is quite enough for a phone; it will charge it. What to do with the rest of the wires? You don't need to do anything with them.

A little history of USB

The development of the Universal Serial Bus or USB began in 1994 by Indian-American engineer Ajay Bhatt of Intel and his division of specialists from leading computer companies called USB-IF (USB Implementers Forum, Inc). The company developing the port included representatives from Intel, Compaq, Microsoft, Apple, LSI and Hewlett-Packard. The developers were faced with the task of inventing a port that was universal for most devices, working on the Plug&Play principle, when the device, after connecting to the computer, either started working immediately or started after installing the necessary software (drivers). The new principle should replace the LPT and COM port, and the data transfer rate should be at least 115 kbit/s. In addition, the port had to be parallel, to organize the connection of several sources to it, and also allow the use of “hot” connection of devices without turning off or rebooting the PC.

The first non-industrial sample of a USB port coded 1.0 with the ability to transfer data up to 12 Mbit/s. was introduced in late 1995 - early 1996. In mid-1998, the port was updated with automatic speed maintenance for a stable connection and could operate at a speed of 1.5 Mbit/s. Its modification became USB 1.1. Starting in mid-1997, the first motherboards and devices with this connector were released. In 2000, USB 2.0 appeared, supporting speeds of 480 Mbit/s. The main design principle is the ability to connect older USB 1.1 devices to the port. At the same time, the first 8 megabyte flash drive for this port appeared. 2008, with improvements to the USB controller in terms of speed and power, was marked by the release of the 3rd version of the port, supporting data transfer at speeds of up to 4.8 Gbit/s.

Basic concepts and abbreviations used when pinouting USB connectors

VCC (Voltage at the Common Collector) or Vbus– positive potential contact of the power supply. For USB devices it is +5 Volts. In radioelectric circuits, this abbreviation corresponds to the supply voltage of bipolar NPN and PNP transistors.

GND (Ground) or GND_DRAIN– negative power contact. In equipment (including motherboards) it is connected to the housing to protect against static electricity and sources of external electromagnetic interference.

D- (Data -)- information contact with zero potential, relative to which data transfer occurs.

D+ (Data+)– information contact with logical “1”, necessary for data transfer from the host (PC) to the device and vice versa. Physically, the process is the transmission of positive rectangular pulses of different duty cycles and an amplitude of +5 Volts.

Male– USB connector plug, popularly referred to as “male”.

Female– USB connector or female.

Series A, Series B, mini USB, micro-A, micro-B, USB 3.0– various modifications of USB device connectors.

RX (receive)– data reception.

TX (transmit)- data transfer.

-StdA_SSRX– negative contact for receiving data in USB 3.0 in SuperSpeed ​​mode.

+StdA_SSRX– positive contact for receiving data in USB 3.0 in SuperSpeed ​​mode.

-StdA_SSTX– negative contact for data transfer to USB 3.0 in SuperSpeed ​​mode.

+StdA_SSTX– positive contact for data transfer to USB 3.0 in SuperSpeed ​​mode.

DPWR– additional power connector for USB 3.0 devices.

USB connector pinout

For specifications 1.x and 2.0, the pinout of the USB connector is identical.

As we can see from the figure, on legs 1 and 4 there is supply voltage for the periphery of the connected device, and information data is transmitted through contacts 2 and 3. If you are using a five-pin micro-USB connector, please refer to the following figure.

As you can see, the use of 4 pins is not provided for in the standard specification. However, sometimes pin 4 is used to supply positive power to the device. Most often, these are energy-intensive consumers with a current tending to the maximum permissible for a USB 2.0 connector, as will be discussed below. According to the standard, each wire has its own color. So the positive power contact is connected by a red wire, the negative one by a black wire, the data- signal goes along white, and the positive information signal data+ goes through green. In addition, to protect devices from external influences, high-quality cables use shielding of the metal parts of the connectors by shorting the outer metallized cable braid to the housing. In other words, the cable shield can be connected to the negative power supply of the connector (but this condition is not necessary). Using a shield allows you to improve the stability of data transmission, increase speed and apply a longer cable length to the device.

If you use a micro-USB – OTG cable to the tablet, the 4th unused contact is connected to the negative wire. The cable diagram is clearly presented in the figure from 4pda.ru. In this case, it is strictly forbidden to supply positive power to the 4th pin of the connector, which will result in failure of either the USB port controller or failure of the OTG controller!

As for the USB 2.0 connector specification, below is a table of the main characteristics.

The specification also indicates that to filter the useful signal, the maximum capacitance between the Data bus and the negative power contact (ground) can be used with a capacitance of up to 10uF (minimum 1uF). It is not recommended to use a higher capacitor value, since at speeds close to the maximum, the pulse fronts are delayed, which leads to a loss of speed characteristics of the USB port.

When connecting external connectors of USB ports to the motherboard, you should pay special attention to the correct connection of the wires, since it is not as dangerous to confuse the Data - and Data + information signals as it is dangerous to swap the power wires. In this case, from the experience of repairing electronic equipment, the connected device often becomes unusable! The connection diagram must be looked at in the instructions for the motherboard.

It remains to add that for the implementation of cables for connected devices of the USB 2.0 connector, a standard for the cross-section of each wire in the cord has been approved.

AWG is the American wire gauge marking system.

Now let's move on to the USB 3.0 port

The second name for a USB 3.0 port is USB Super Speed, due to the increased data transfer speed of up to 5 Gb/sec. To increase speed indicators, engineers used full-duplex (two-wire) transmission of both sent and received data. Due to this, 4 additional contacts appeared in the connector -/+ StdA_SSRX and -/+StdA_SSTX. In addition, increased speeds required the use of a new type of controller with higher power consumption, which led to the need to use additional power pins in the USB 3.0 connector (DPWR and DGND). The new type of connector began to be called USB Powered B. In a digression, let’s say that the first Chinese flash drives for this connector were made in cases without taking into account the thermal characteristics of their controllers and, as a result, they got very hot and failed.

The practical implementation of the USB 3.0 port made it possible to achieve a data exchange rate of 380 MB/sec. For comparison, the SATA II port (connecting hard drives) is capable of transferring data at a speed of 250 MB/sec. The use of additional power allowed the use of devices with a maximum current consumption of up to 900mA on the socket. This way, either one device or up to 6 gadgets with a consumption of 150mA can be connected. In this case, the minimum operating voltage of the connected device can be reduced to 4V. Due to the increase in connector power, engineers had to limit the length of the USB 3.0 cable to 3 m, which is an undoubted disadvantage of this port. Below we provide the standard USB 3.0 port specification

The pinout of the USB 3.0 connector is as follows:

Operating systems starting with Windows 8, MacBook Air and MacBook Pro latest versions and Linux with kernel version 2.6.31 have full software support for the USB 3.0 specification. Due to the use of two additional power contacts in the USB 3.0 Powered-B connector, it is possible to connect devices with a load capacity of up to 1A.

The USB interface began to be widely used about 20 years ago, to be precise, since the spring of 1997. It was then that the universal serial bus was implemented in hardware in many personal computer motherboards. Currently, this type of connecting peripherals to a PC is a standard, versions have been released that have significantly increased the data exchange speed, and new types of connectors have appeared. Let's try to understand the specifications, pinouts and other features of USB.

What are the advantages of Universal Serial Bus?

The introduction of this connection method made it possible:

• Quickly connect various peripheral devices to your PC, from the keyboard to external disk drives.
• Make full use of Plug&Play technology, which simplifies the connection and configuration of peripherals.
• Refusal of a number of outdated interfaces, which had a positive impact on the functionality of computing systems.
• The bus allows not only to transfer data, but also to supply power to connected devices, with a load current limit of 0.5 and 0.9 A for the old and new generations. This made it possible to use USB to charge phones, as well as connect various gadgets (mini fans, lights, etc.).
• It has become possible to manufacture mobile controllers, for example, a USB RJ-45 network card, electronic keys for entering and exiting the system

Types of USB connectors - main differences and features

There are three specifications (versions) of this type of connection that are partially compatible with each other:

1. The very first version that has become widespread is v 1. It is an improved modification of the previous version (1.0), which practically did not leave the prototype phase due to serious errors in the data transfer protocol. This specification has the following characteristics:

• Dual-mode data transfer at high and low speed (12.0 and 1.50 Mbps, respectively).
• Possibility of connecting more than a hundred different devices (including hubs).
• The maximum cord length is 3.0 and 5.0 m for high and low transfer speeds, respectively.
• The rated bus voltage is 5.0 V, the permissible load current of the connected equipment is 0.5 A.

Today this standard is practically not used due to its low throughput.

1. The dominant second specification today... This standard is fully compatible with the previous modification. A distinctive feature is the presence of a high-speed data exchange protocol (up to 480.0 Mbit per second).

Due to full hardware compatibility with the younger version, peripheral devices of this standard can be connected to the previous modification. True, the throughput will decrease up to 35-40 times, and in some cases more.

Since these versions are fully compatible, their cables and connectors are identical.

Please note that, despite the bandwidth specified in the specification, the actual data exchange speed in the second generation is somewhat lower (about 30-35 MB per second). This is due to the implementation of the protocol, which leads to delays between data packets. Since modern drives have a read speed four times higher than the throughput of the second modification, that is, it does not meet current requirements.

1. The 3rd generation universal bus was developed specifically to solve problems of insufficient bandwidth. According to the specification, this modification is capable of exchanging information at a speed of 5.0 Gbit per second, which is almost three times the reading speed of modern drives. Plugs and sockets of the latest modification are usually marked blue to facilitate identification of belonging to this specification.

Another feature of the third generation is an increase in the rated current to 0.9 A, which allows you to power a number of devices and eliminate the need for separate power supplies for them.

As for compatibility with the previous version, it is partially implemented; this will be discussed in detail below.

Classification and pinout

Connectors are usually classified by type, there are only two of them:

Note that such convectors are compatible only between earlier modifications.

In addition, there are extension cables for the ports of this interface. At one end there is a type A plug, and at the other there is a socket for it, that is, in fact, a “mother” - “father” connection. Such cords can be very useful, for example, to connect a flash drive without crawling under the table to the system unit.

Now let's look at how contacts are wired for each of the types listed above.

USB 2.0 connector pinout (types A and B)

Since the physical plugs and sockets of early versions 1.1 and 2.0 do not differ from each other, we will present the wiring of the latter.

Figure 6. Wiring the plug and socket of type A connector

Designation:

• A – nest.
• B – plug.
• 1 – power supply +5.0 V.
• 2 and 3 signal wires.
• 4 – mass.

In the figure, the coloring of the contacts is shown according to the colors of the wire, and corresponds to the accepted specification.

Now let's look at the wiring of the classic socket B.

Designation:

• A – plug connected to the socket on peripheral devices.
• B – socket on a peripheral device.
• 1 – power contact (+5 V).
• 2 and 3 – signal contacts.
• 4 – ground wire contact.

The colors of the contacts correspond to the accepted colors of the wires in the cord.

USB 3.0 pinout (types A and B)

In the third generation, peripheral devices are connected via 10 (9 if there is no shielding braid) wires; accordingly, the number of contacts is also increased. But they are located in such a way that it is possible to connect devices of earlier generations. That is, the +5.0 V contacts, GND, D+ and D-, are located in the same way as in the previous version. The wiring for Type A socket is shown in the figure below.

Figure 8. Pinout of Type A connector in USB 3.0

Designation:

• A – plug.
• B – nest.
• 1, 2, 3, 4 – connectors fully correspond to the pinout of the plug for version 2.0 (see B in Fig. 6), the colors of the wires also match.
• 5 (SS_TX-) and 6 (SS_TX+) connectors for data transmission wires via the SUPER_SPEED protocol.
• 7 – ground (GND) for signal wires.
• 8 (SS_RX-) and 9 (SS_RX+) connectors for data receiving wires using the SUPER_SPEED protocol.

The colors in the figure correspond to those generally accepted for this standard.

As mentioned above, a plug from an earlier model can be inserted into the socket of this port; accordingly, the throughput will decrease. As for the plug of the third generation of the universal bus, it is impossible to insert it into the sockets of the early release.

Now let's look at the pinout for the type B socket. Unlike the previous type, such a socket is incompatible with any plug of earlier versions.

Designations:

A and B are plug and socket, respectively.

Digital signatures for contacts correspond to the description in Figure 8.

The color is as close as possible to the color markings of the wires in the cord.

Micro USB connector pinout

To begin with, we present the wiring for this specification.

As can be seen from the figure, this is a 5 pin connection; both the plug (A) and socket (B) have four contacts. Their purpose and digital and color designation correspond to the accepted standard, which was given above.

Description of the micro USB connector for version 3.0.

For this connection, a characteristically shaped 10 pin connector is used. In fact, it consists of two parts of 5 pin each, and one of them fully corresponds to the previous version of the interface. This implementation is somewhat confusing, especially considering the incompatibility of these types. Probably, the developers planned to make it possible to work with connectors of earlier modifications, but subsequently abandoned this idea or have not yet implemented it.

The figure shows the pinout of the plug (A) and the appearance of the micro USB socket (B).

Contacts 1 to 5 fully correspond to the second generation micro connector, the purpose of the other contacts is as follows:

• 6 and 7 – data transmission via high-speed protocol (SS_TX- and SS_TX+, respectively).
• 8 – mass for high-speed information channels.
• 9 and 10 – data reception via high-speed protocol (SS_RX- and SS_RX+, respectively).

Mini USB pinout

This connection option is used only in early versions of the interface; in the third generation this type is not used.

As you can see, the wiring of the plug and socket is almost identical to the micro USB, respectively, the color scheme of the wires and the contact numbers are also the same. Actually, the differences are only in shape and size.

In this article we have presented only standard types of connections; many manufacturers of digital equipment practice introducing their own standards; there you can find connectors for 7 pin, 8 pin, etc. This introduces certain difficulties, especially when the question arises of finding a charger for a mobile phone. It should also be noted that manufacturers of such “exclusive” products are in no hurry to tell how the USB pinout is done in such contactors. But, as a rule, this information is easy to find on thematic forums.

The USB type connector is widely used as an interface connector for household devices, and is also actively penetrating into the professional sphere. Provides information exchange between various modern electronic devices, as well as remote power supply of low-power terminal devices.

Interface cables with USB connectors are widely available on sale. In practice, there is a need for a homemade connecting cord of this type, which replaces a failed or simply lost purchased cable, provides the required length, or there is a need for an adapter between USB ports of different types.

Features of USB connectors

In total, three main versions of USB interfaces were standardized. Each new one provided an increase in the speed of information volume and increased functionality. At the same time, taking into account the expansion of application areas, the form factor of the plugs changed.

The ability to connect a cable to a device automatically means that the connected devices are compatible with each other.

USB cable plugs come in full, mini and micro form factors. A type A plug is always included in the central device; a type B plug is intended for servicing the peripheral device. In addition, plugs are divided into type M (from the English male - plug) and F (from the English female - socket).

USB cable wiring by color

PinoutUSB connector differs in that version 2 interface cables use four wires (mini and micro versions - 5 wires), while in version 3 the number of wires is increased to nine.

USB connector wiring made easier by the fact that the wires of a standard cable are assigned specific colors, shown in the table below.

Wire number	USB2	USB3
1	red (plus power)	red (plus power)
2	white (data)	white (data)
3	green (data)	green (data)
4		black (zero power or common)
5	—	blue (USB3 – transfer)
6	—	yellow (USB3 – transfer)
7	—	Earth
8	—	purple (USB3-receive)
9	—	orange (USB3 – reception)

The fifth wire in mini and micro connectors of type B is not used, but in connectors of type A it is shorted to the GND wire.

The screen drain wire (if present) is not assigned a separate number.

A summary of the distribution of wires of USB interfaces version 2 across the pins of various types of plugs is shown in the figure below.

USB cable wiring by color

USB 3.0 pinout

For USB version 3, the pin layout is shown in the figure below.

USB 3.0 cable wiring by color

When making a cable, individual wires and shields are soldered to the corresponding contacts of the plugs.

USB (Universal Serial Bus) - The USB data transfer interface is widespread today, used in almost all devices - phones, PCs, MFPs, tape recorders and other devices - used both for data transfer and for charging phone batteries.

Types of USB connectors.

There are a large number of types of USB connectors. All of them are shown below.

Type A- active, power supply device (computer, host). Type B- passive, connected device (printer, scanner)

USB cable pinout by color.

USB 2.0 pinout.

USB is a serial bus. It uses 4 shielded wires: two for power (+5v & GND) and two for differential data signals (labeled D+ and D-).

USB micro

USB micro has been used since 2011 in phones, MP3 and other devices. Micro is a newer variation of the mini connector. It has the advantage of connecting connectors, the connector is connected tightly to the plug and provides a tight connection.