The USB interface is a popular form of technological communication on mobile and other digital devices. Connectors of this kind are often found on personal computers of various configurations, peripheral computer systems, on cell phones etc.
A feature of the traditional interface is the USB pinout of a small area. For operation, only 4 pins (contacts) + 1 ground shield line are used. True, the latest more advanced modifications (USB 3.0 Powered-B or Type-C) are characterized by an increase in the number of working contacts.
The abbreviation “USB” carries an abbreviated designation, which in its entirety reads as “Universal Series Bus” - a universal serial bus, thanks to the use of which high-speed digital data exchange is carried out.
The versatility of the USB interface is noted:
- low power consumption;
- unification of cables and connectors;
- simple logging of data exchange;
- high level of functionality;
- Wide support for drivers for various devices.
What is the structure of the USB interface, and what types of USB technology connectors exist in modern world electronics? Let's try to figure it out.
Technological structure of the USB 2.0 interface
Connectors related to products included in the specification group 1.x - 2.0 (created before 2001) are connected to a four-core electrical cable, where two conductors are power and two more are transmitting data.
Also in specifications 1.x - 2.0, the wiring of service USB connectors involves connecting a shielding braid - essentially a fifth conductor.
This is what the physical design of normal USB connectors belonging to the second specification looks like. On the left are the “male” type versions, on the right are the “female” type versions and the pinout corresponding to both options
Existing versions of universal serial bus connectors of the noted specifications are presented in three options:
- Normal– type “A” and “B”.
- Mini– type “A” and “B”.
- Micro– type “A” and “B”.
The difference between all three types of products lies in the design approach. If normal connectors are intended for use on stationary equipment, “mini” and “micro” connectors are made for use in mobile devices.
This is what the physical design of the connectors of the second specification from the “mini” series looks like and, accordingly, the label for Mini USB connectors - the so-called pinout, based on which the user makes the cable connection
Therefore, the last two types are characterized by a miniature design and a slightly modified connector shape.
Pinout table for standard type “A” and “B” connectors
Along with the execution of connectors of the “mini-A” and “mini-B” types, as well as connectors of the “micro-A” and “micro-B” types, there are modifications of the “mini-AB” and “micro-AB” type connectors.
A distinctive feature of such designs is the wiring of the USB conductors on a 10-pin pad. However, in practice, such connectors are rarely used.
Micro USB and Mini interface pinout table USB connectors type "A" and "B"
Technological structure of USB 3.x interfaces
Meanwhile, the improvement of digital equipment had already led to the obsolescence of specifications 1.x - 2.0 by the time of 2008.
These interface types did not allow connection new equipment, for example, external hard drives, in such a way that a higher (more than 480 Mbit/s) data transfer rate is provided.
Accordingly, a completely different interface was born, marked with specification 3.0. The development of the new specification is characterized not only by increased speed, but also by increased current - 900 mA versus 500 mA for USB 2/0.
It is clear that the appearance of such connectors has made it possible to service a larger number of devices, some of which can be powered directly from the universal serial bus interface.
Modification of USB 3.0 connectors different types: 1 – “mini” version of type “B”; 2 – standard product type “A”; 3 – development of the “micro” series of type “B”; 4 – Standard type “C”
As you can see in the picture above, the interfaces of the third specification have more working contacts (pins) than the previous - second version. However, the third version is fully compatible with the “two”.
In order to be able to transmit signals at a higher speed, the designers of the third version equipped an additional four data lines and one neutral wire line. Augmented contact pins are located in a separate row.
Pin designation table for connectors of the third version for wiring a USB cable
| Contact | Execution "A" | Execution "B" | Micro-B |
| 1 | Power + | Power + | Power + |
| 2 | Data - | Data - | Data - |
| 3 | Data + | Data + | Data + |
| 4 | Earth | Earth | Identifier |
| 5 | StdA_SSTX – | StdA_SSTX – | Earth |
| 6 | StdA_SSTX+ | StdA_SSTX+ | StdA_SSTX – |
| 7 | GND_DRAIN | GND_DRAIN | StdA_SSTX+ |
| 8 | StdA_SSRX – | StdA_SSRX – | GND_DRAIN |
| 9 | StdA_SSRX + | StdA_SSRX + | StdA_SSRX – |
| 10 | – | – | StdA_SSRX + |
| 11 | Shielding | Shielding | Shielding |
Meanwhile, the use of the USB 3.0 interface, in particular the “A” series, turned out to be a serious design flaw. The connector has an asymmetrical shape, but the connection position is not specifically indicated.
The developers had to modernize the design, as a result of which in 2013 a USB-C option appeared at users’ disposal.
Upgraded USB 3.1 connector
The design of this type of connector involves duplication of working conductors on both sides of the plug. There are also several backup lines on the interface.
This type of connector is widely used in modern mobile digital technology.
Location of contacts (pins) for the interface USB-C type, belonging to the series of the third specification of connectors intended for communications of various digital equipment
Characteristics worth noting USB Type-C. For example, the speed parameters for this interface show a level of 10 Gbit/s.
The design of the connector is compact and ensures a symmetrical connection, allowing the connector to be inserted in any position.
Pinout table compliant with Specification 3.1 (USB-C)
| Contact | Designation | Function | Contact | Designation | Function |
| A1 | GND | Grounding | B1 | GND | Grounding |
| A2 | SSTXp1 | TX+ | B2 | SSRXp1 | RX+ |
| A3 | SSTXn1 | TX – | B3 | SSRXn1 | RX- |
| A4 | Tire + | Power + | B4 | Tire + | Power + |
| A5 | CC1 | CFG channel | B5 | SBU2 | PPD |
| A6 | Dp1 | USB 2.0 | B6 | Dn2 | USB 2.0 |
| A7 | Dn1 | USB 2.0 | B7 | Dp2 | USB 2.0 |
| A8 | SBU1 | PPD | B8 | CC2 | CFG |
| A9 | Tire | Nutrition | B9 | Tire | Nutrition |
| A10 | SSRXn2 | RX- | B10 | SSTXn2 | TX – |
| A11 | SSRXp2 | RX+ | B11 | SSTXp2 | TX+ |
| A12 | GND | Grounding | B12 | GND | Grounding |
The next level of the USB 3.2 specification
Meanwhile, the process of improving the universal serial bus is actively continuing. At the non-commercial level, the next level of specification has already been developed - 3.2.
According to available information, the speed characteristics of the USB 3.2 interface promise twice the parameters than the previous design is capable of.
The developers managed to achieve such parameters by introducing multi-band channels through which transmission is carried out at speeds of 5 and 10 Gbit/s, respectively.
Similar to "Thunderbolt", USB 3.2 uses multiple lanes to achieve overall throughput, rather than trying to sync and run the same channel twice
By the way, it should be noted that the compatibility of the promising interface with the existing USB-C is fully supported, since the “Type-C” connector (as already noted) is equipped with backup contacts (pins) that provide multi-band signal transmission.
Features of cable wiring on connector contacts
There are no special technological nuances associated with soldering cable conductors on the contact pads of connectors. The main thing in this process is to ensure that the color of the cable conductors matches specific contact(kick).
Color coding of conductors within a cable assembly used for USB interfaces. Shown from top to bottom, respectively, is the color scheme of cable conductors for specifications 2.0, 3.0 and 3.1
Also, if you are wiring modifications of outdated versions, you should take into account the configuration of the connectors, the so-called “male” and “female”.
The conductor soldered on the male contact must match the soldering on the female contact. Take, for example, the option of wiring the cable to USB 2.0 pins.
The four working conductors used in this embodiment are usually marked in four different colors:
- red;
- white;
- green;
- black.
Accordingly, each conductor is soldered onto a pad marked with a connector specification of a similar color. This approach greatly simplifies the work of an electronics engineer and eliminates possible mistakes during the desoldering process.
A similar soldering technology is applied to connectors of other series. The only difference in such cases is the larger number of conductors that have to be soldered.
Regardless of the connector configuration, screen conductor soldering is always used. This conductor is soldered to the corresponding contact on the connector, Shield – protective screen.
Cases of being ignored are not uncommon. protective screen, when “experts” do not see the point in this conductor. However, the lack of a screen dramatically reduces the performance of the USB cable.
Therefore, it is not surprising when, with a significant length of cable without a screen, the user experiences problems in the form of interference.
Wiring the connector with two conductors to organize a power line for the donor device. In practice, different wiring options are used, based on technical needs.
The USB cable can be soldered in different ways, depending on the configuration of the port lines on specific device.
For example, to connect one device to another in order to obtain only a supply voltage (5V), it is enough to solder only two lines on the corresponding pins (contacts).
Conclusions and useful video on the topic
The video below explains the main points of pinout of connectors of the 2.0 series and others, and visually explains individual details of the production of soldering procedures.
Owning complete information By pinouting the Universal Serial Bus connectors, you can always cope with a technical problem associated with conductor defects. This information will also come in handy if you need to connect some digital devices in a non-standard way.
This article provides general information about the USB standard, as well as pinoutUSB connector by colors of all types (USB, mini-USB, micro-USB, USB-3.0).
USB (Universal Serial Bus) connector is a universal-purpose serial bus, modern way connections external devices To personal computer. Replaces previously used connection methods (serial and parallel port, PS/2, Gameport, etc.) for conventional views peripheral devices— printers, mice, keyboards, joysticks, cameras, modems, etc. This connector also allows you to organize data exchange between a computer and a video camera, card reader, MP3 player, or external hard drive.
The advantage of the USB connector over other connectors is the ability to connect Plug&Play devices without the need to restart the computer or manual installation drivers. Plug&Play devices can be connected while the computer is running and be up and running within seconds.
When connecting a new device, first the hub (cable hub) receives high level via a data line, which reports that new equipment has arrived. Then the following steps follow:
- The Hub informs the Host computer that a new device has been connected.
- The host computer asks the hub which port the device was connected to.
- After receiving a response, the computer issues a command to activate this port and resets the bus.
- The hub generates a reset signal (RESET) with a duration of 10 ms. The output power current of the device is 100 mA. The device is now ready for use and has a default address.
The creation of USB is the result of collaboration between companies such as Compaq, NEC, Hewlett-Packard, Philips, Intel, Lucent and Microsoft. The USB standard was intended to replace the widely used RS-232 serial port. USB generally makes work easier for the user and has a greater throughput than the RS-232 serial port. The first USB specification was developed in 1995 as a low-cost, universal interface for connecting external devices that did not require much data bandwidth.
Three USB versions
USB 1.1
Version USB 1.1 was designed to serve slow peripheral devices (Low-Speed) with a data transfer rate of 1.5 Mbit/s and fast devices(Full-Speed) with a data transfer rate of 12 Mbit/s. USB 1.1, however, was unable to compete with the high-speed interface, for example. FireWire (IEEE 1394) from Apple with data transfer rates up to 400 Mbps.
USB 2.0
In 1999, they began to think about the second generation of USB, which would be applicable to more complex devices (for example, digital video cameras). This a new version, referred to as USB 2.0, was released in 2000 and provided a maximum speed of up to 480 Mbps in Hi-Speed mode and retained backwards compatible with USB 1.1 (data transfer type: Full-Speed, Low-Speed).
USB 3.0
The third version (also referred to as Super-speed USB) was designed in November 2008, but was probably delayed until 2010 due to the financial crisis. USB 3.0 has more than 10 times the speed of USB 2.0 (up to 5 Gbit/s). The new design has 9 wires instead of the original 4 (the data bus already consists of 4 wires), however, this standard still supports USB 2.0 and provides lower power consumption. This allows you to use any combination of USB 2.0 and USB 3.0 devices and ports.
The USB connector has 4 pins. Connects to DATA+ and DATA- contacts twisted pair(two wires twisted together), and regular wires are connected to the VCC (+5 V) and GND pins. Then the entire cable (all 4 wires) is shielded with aluminum foil.
Below is the pinout (wiring) of all types of USB connectors.
Types and pinout of USB connectors
USB cable pinout by color:
- +5 volts
- -Data
- +Data
- General
USB connector pinout diagram - type A:
USB connector pinout diagram - type B:
Cable wiring according to connector colors:mini (mini) and micro (micro) USB:
- +5 volts
- -Data
- +Data
- Not used / Shared
- General
Mini-USB connector pinout - type A:
One of the most common methods of connecting peripheral devices to a computer or laptop seems to be using USB connector Such a connection has significant advantages compared to outdated analogues, and the simplicity of its pinout allows even beginners to do it manually.
What is USB?
This format connection began to be widely used relatively recently, although it was developed in the 90s. The reason for this delay was the presence of numerous analogues that surpassed a similar connection standard in data transfer speed, as well as in a number of other parameters.
To date, this connection is a special serial bus, the wide range of applications of which makes it truly universal. This format has successfully replaced many other connection options used previously. These include serial and parallel ports, Gameport, and PS/2.
Its difference is the ability to use one connection for a number of third-party devices. Among them are:
One of the key advantages of this format over analogues is the ability to use the connected device after a short period of time, without the need to restart the PC or laptop. In addition, it can be used to power or charge the device. When using it, there is no need to install drivers manually, which significantly simplifies preparing the gadget for use.
How does the connection work?
Considering connecting any device to a computer, performed through USB cable, several stages of work should be distinguished. First, the hub receives a high level through the data line, which signals that connected equipment has been detected.
Then, in connection operation it is permissible highlight several stages:
- The hub informs the PC that a new device is connected;
- The PC queries the hub regarding the port used for connection;
- The PC activates the port in use and performs a bus reset;
- The hub sends a reset signal, the duration of which is 10 ms.
At the output, the current intended for power supply reaches 100 mA, after which the device is completely ready for use. Likewise, any device connected via USB quickly becomes usable, without reboots or significant waits.
Types of USB
Among all existing USB connections, there are three main versions. USB 1.1 was designed to work with slow devices whose data transfer speed was about 1.5 MB/s. For a high-speed connection, using such a format was impractical, since there were many more productive analogues, for example, FireWire.
In 2000, a new version was released - USB 2.0, which was distinguished by its ability to work with high-speed devices, as well as general compatibility with slower analogues, due to which it became widespread. USB pinout 2.0 is carried out according to the standard algorithm.
The third generation of USB was developed in 2008, but mass use began only in 2010. The main difference was that 9 wires were used for pinout, instead of the standard four, which allowed the interface to become 10 times faster. At the same time, four wires are still used for data transmission, and the interface itself remains compatible with the previous 2.0 generation. USB 3.0 pinout is similar to version 2.0.
Connector pinout
Standard connector has four contacts, which differ in the color of the wires that need to be connected to them. Any of the connection options will power the device. Among the wires involved in the plug:
- +5 volts - red;
- -data – white;
- +data - green;
- General - black.
If you position the connector in relation to you, and the characteristic USB sign is at the top, then they will be located in the reverse order, starting with black from left to right. If you need to pinout mini- usb or micro-usb connectors, then there will be five contacts at once (two common wires - black and purple). The second common wire is connected before the last one, black.
If you use a Mini-AF type of plug, then positioning it with the connector narrowing upward, you should solder the contacts from left to right, starting with the black common wire. USB Mini-AM assumes the opposite pinout option, starting with the red wire.
Mini-BF is positioned with a narrowing upward and soldered according to the Mini - AF principle, and in the case of Mini-BM, it uses the Mini-Am pinout method. Most often, AF connectors are used as charging for Samsung tablets.
Micro-USB wiring also has a similar pattern: for Micro-AF and Micro-BF, the contacts are connected starting with the +5 volt wire (red), and Micro-AM and Micro-BM (used in devices Samsung Galaxy as charging) are soldered in the reverse order, starting with the black common wire. When performing work, it is strongly recommended to use illustrations in order to eliminate accidental errors.
USB (Universal Serial Bus- “universal serial bus”) - a serial data transfer interface for medium- and low-speed peripheral devices. A 4-wire cable is used for connection, with two wires used to receive and transmit data, and 2 wires to power the peripheral device. Thanks to the built-in lines USB power supply allows you to connect peripheral devices without its own power supply.
USB Basics
USB cable consists of 4 copper conductors - 2 power conductors and 2 data conductors in twisted pair, and a grounded braid (screen).USB cables have physically different tips “to the device” and “to the host”. It is possible to implement a USB device without a cable, with a “to-host” tip built into the housing. It is also possible to permanently integrate the cable into the device(for example, USB keyboard, Web camera, USB mouse), although the standard prohibits this for full and high speed devices.
USB bus strictly oriented, i.e. it has the concept of a “master device” (host, also known as a USB controller, usually built into the south bridge chip on motherboard) and "peripheral devices".
Devices can receive +5 V power from the bus, but may also require external source nutrition. A standby mode is also supported for devices and splitters upon command from the bus, removing the main power while maintaining standby power and turning it on upon command from the bus.
USB supportsHot plugging and unplugging of devices. This is possible due to the increase in the length of the grounding contact conductor in relation to the signal ones. When connected USB connector are the first to close grounding contacts, the potentials of the housings of the two devices become equal and further connection of the signal conductors does not lead to overvoltages, even if the devices are powered from different phases of a three-phase power network.
At the logical level USB device supports transactions for receiving and transmitting data. Each packet of each transaction contains a number endpoint on the device. When a device is connected, drivers in the OS kernel read a list of endpoints from the device and create control data structures to communicate with each endpoint on the device. The collection of endpoints and data structures in the OS kernel is called pipe.
Endpoints, and therefore channels, belong to one of 4 classes:
- continuous (bulk),
- manager (control),
- isochronous (isoch),
- interrupt.
Low speed devices such as a mouse cannot have isochronous and flow channels.
Control channel designed for exchanging short question-answer packets with the device. Any device has control channel 0, which allows software The OS reads brief information about the device, including manufacturer and model codes used to select a driver, and a list of other endpoints.
Interrupt channel allows you to deliver short packets in both directions, without receiving a response/confirmation, but with a guarantee of delivery time - the packet will be delivered no later than in N milliseconds. For example, used in input devices (keyboards, mice or joysticks).
Isochronous channel allows you to deliver packets without a guarantee of delivery and without replies/confirmations, but with a guaranteed delivery speed of N packets per bus period (1 KHz for low and full speed, 8 KHz for high speed). Used to transmit audio and video information.
Flow channel provides a guarantee of delivery of each packet, supports automatic suspension of data transmission due to device reluctance (buffer overflow or underrun), but does not guarantee delivery speed and delay. Used, for example, in printers and scanners.
Bus time is divided into periods, at the beginning of the period the controller transmits the “beginning of period” packet to the entire bus. Then, during the period, interrupt packets are transmitted, then isochronous ones in the required quantity; for the remaining time in the period, control packets are transmitted, and lastly, stream packets.
Active side of the bus is always the controller, the transfer of a data packet from the device to the controller is implemented as a short question from the controller and a long response from the device containing data. The packet movement schedule for each bus period is created jointly by the controller hardware and driver software; for this, many controllers use Direct Memory Access DMA (Direct Memory Access) - mode of data exchange between devices or between the device and the main memory, without participation Central Processor (CPU). As a result, the transfer speed is increased since data is not sent back and forth to the CPU.
The packet size for an endpoint is a constant built into the device's endpoint table and cannot be changed. It is selected by the device developer from among those supported by the USB standard.
USB Specifications
Features, advantages and disadvantages of USB:
- High transfer speed (full-speed signaling bit rate) - 12 Mb/s;
- The maximum cable length for high transfer speed is 5 m;
- Low-speed signaling bit rate - 1.5 Mb/s;
- The maximum cable length for low communication speed is 3 m;
- Maximum connected devices (including multipliers) - 127;
- It is possible to connect devices with different baud rates;
- There is no need to install additional elements such as terminators;
- Supply voltage for peripheral devices - 5 V;
- The maximum current consumption per device is 500 mA.
USB signals are transmitted over two wires of a shielded 4-wire cable.
USB 1.0 and USB 2.0 connector pinout
| Type A | Type B | ||
| Fork (on cable) |
Socket (on the computer) |
Fork (on cable) |
Socket (on peripheral device) |
 |
|||
Names and functional assignments of USB 1.0 and USB 2.0 pins
Disadvantages of USB 2.0
At least the maximum transmission speed USB data 2.0 is 480 Mbit/s (60 MB/s), in real life achieving such speeds is unrealistic (~33.5 MB/sec in practice). This is due to the large delays on the USB bus between the request for data transfer and the actual start of the transfer. For example, FireWire, although it has a lower peak throughput of 400 Mbps, which is 80 Mbps (10 MB/s) less than USB 2.0, actually allows for greater data transfer throughput to hard drives and other storage devices. In this regard, various mobile drives have long been limited by the insufficient practical bandwidth of USB 2.0.
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Victor Pankov sent an interesting link to an article that describes in detail the pinout features USB connectors for correct charging of various gadgets, because it is no secret that gadgets often refuse to charge from a simple USB port of a drive or computer, or do not behave as we would like.
Most modern gadgets ( mobile phones, smartphones, players, e-books, tablets, etc.) supports charging via a USB mini/micro socket. There may be several connection options:
The device can be charged from a PC via a standard data cable. Usually this is a USB_AM-USB_BM_mini/micro cable. If a device requires a current of more than 0.5 A to charge (this is the maximum that USB 2.0 is capable of), then the charging time can be painfully long, even indefinitely. USB port 3.0 (the little blue one) already produces 0.9 A, but this may not seem enough to some.
Using the same data cable, your device can be charged from its original one. charger(network or car), equipped with a 4-pin USB-AF socket, like on a computer. Of course, this is no longer a real USB port. The charger socket only outputs approximately 5V between pins 1 and 4 of the 4-pin socket (plus on pin #1, minus on pin #4). Well, all sorts of jumpers and resistors can be installed between different contacts of the socket. For what? This witchcraft will be discussed below.
The gadget can be connected to a third-party or homemade charger that provides 5 volts. And this is where the fun begins...
If you try to charge from someone else's charger with USB output your gadget may refuse to charge under the pretext that the charger allegedly does not suit it. The answer is that many phones/smartphones “look” at how the Data+ and Data- wires are connected, and if the gadget doesn’t like something, the charger will be rejected.
Nokia, Philips, LG, Samsung, HTC and many other phones will only recognize the charger if the Data+ and Data- pins (2nd and 3rd) are shorted. You can short them in the USB_AF socket of the charger and easily charge your phone via a standard data cable.
If the charger already has an output cord (instead of an output jack), and you need to solder a mini/micro USB plug to it, then do not forget to connect pins 2 and 3 in the mini/micro USB itself. In this case, you solder the plus to 1 contact, and the minus to the 5th (last).
U iPhones In general, there are some occult requirements for switching the charger socket: the Data+ (2) and Data- (3) contacts must be connected to the GND contact (4) through 49.9 kΩ resistors, and to the +5V contact through 75 kΩ resistors.
Motorola“requires” a 200 kOhm resistor between pins 4 and 5 of the USB micro-BM plug. Without a resistor, the device does not charge until it is completely charged.
To charge Samsung Galaxy The USB micro-BM plug must have a 200 kOhm resistor between pins 4 and 5 and a jumper between pins 2 and 3.
For a more complete and “humane” charge of the tablet Samsung Galaxy Tab They recommend another circuit: two resistors: 33 kOhm between +5 and the D-D+ jumper; 10 kOhm between GND and jumper D-D+.
Apparatus E-ten(“Raccoon”) is not interested in the state of these contacts, and will support even a simple charger. But it has an interesting requirement for the charging cable - the “Raccoon” charges only if pins 4 and 5 are short-circuited in the mini-USB plug.
If you don’t want to bother with a soldering iron, you can buy a USB-OTG cable - in its mini-USB plug, pins 4 and 5 are already closed. But then you will also need a USB AM-AM adapter, that is, “male”-“male”.
The Ginzzu GR-4415U car charger and its analogues, which claim to be universal, are equipped with two output sockets: “HTC/Samsung” and “Apple” or “iPhone”. The pinout of these sockets is shown below.
For power or charge Garmin navigator A special data cable is required. Just to power the navigator via a data cable, you need to short-circuit pins 4 and 5 of the mini-USB plug. To recharge, you need to connect pins 4 and 5 through an 18 kOhm resistor:
So, if you want to convert a regular charger into a USB charger for your phone:
Make sure the device produces approximately 5 volts DC voltage
Find out if this charger is capable of delivering a current of at least 500 mA
Make any necessary changes to the USB-AF jack or USB-mini/micro plug connections