USB connector what. What's on USB Type-C now?

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Today’s article will be devoted, as the title suggests, to discussing the basics USB interface . Let's look at the basic concepts, the interface structure, figure out how data transfer occurs, and in the near future we'll put all this into practice 😉 In short, let's get started!

There are a number of different specifications USB. It all started with USB 1.0 And USB 1.1, then the interface evolved into USB 2.0, the final specification appeared relatively recently USB 3.0. But on this moment the most common implementation is USB 2. 0.

Well, for starters, the main points and characteristics. USB 2.0 supports three operating modes:

High Speed– up to 480 Mb/s
Full Speed– up to 12 Mb/s
Low Speed– up to 1.5 Mb/s

Commands on the bus USB host(for example, a PC), to which you can connect up to 127 different devices. If this is not enough, then you need to add another host. Moreover, it is important that the device itself cannot send/receive data to/from the host; it is necessary for the host to contact the device itself.

Almost all articles about USB I've seen the term used end point“, but what it is is usually written rather vaguely. So, the endpoint is part of the device USB, which has its own unique identifier. Every device USB may have multiple endpoints. By and large, an endpoint is just an area of memory USB a device in which any data can be stored (data buffer). And in the end we get this - each device has its own unique address on the bus USB, and each endpoint of this device has its own number. Like this)

Let's digress a little and talk about the “hardware” part of the interface.

There are two types of connectors – Type A and Type B.

As is already clear from the figure Type A always faces the host. These are the connectors we see on computers and laptops. Connectors Type B always refer to connected USB devices. The USB cable consists of 4 wires of different colors. Well, actually, red is power (+5 V), black is ground, white and green are for data transmission.

In addition to those shown in the figure, there are also other options for USB connectors, for example, mini-USB and others, well, you already know that 😉

It’s probably worth touching a little on the method of data transfer, but we won’t go deeper into this) So, when transferring data over the bus USB the coding principle is used NRZI(no return to zero with inversion). To transmit logical “1”, it is necessary to increase the level of the D+ line above +2.8 V, and the level of the D- line must be lowered below +0.3 V. To transmit zero, the situation is the opposite - (D- > 2.8 V) and (D+< 0.3 В).

We should also discuss the power supply of devices USB. And here, too, several options are possible.

Firstly, devices can be powered from the bus, then they can be divided into two classes:

Low-power
High-power

The difference here is that low-power devices cannot consume more than 100 mA. A devices high-power should consume no more 100 mA only at the configuration stage. Once configured by the host, their consumption can be up to 500 mA.

In addition, devices may have their own power supply. In this case, they can receive up to 100 mA from the bus, and take everything else from your source)

This seems to be all, let's slowly move on to the structure of the transmitted data. Still, this is of greatest interest to us 😉

All information is transmitted personnel, which are sent at regular intervals. In turn, each frame consists of transactions. Perhaps it will be clearer this way:

Each frame includes a package , then transactions for different endpoints follow, and it all ends with a package EOF (End Of Frame). To be absolutely precise, then EOF- this is not quite a packet in the usual sense of the word - it is an interval of time during which data exchange is prohibited.

Each transaction has the following form:

The first package (called Token plastic bag) contains information about the device address USB, as well as the number of the endpoint to which this transaction is intended. In addition, this package stores information about the type of transaction (we will discuss what types there are, but a little later =)). – everything is clear with him, this is the data transmitted by the host or the endpoint (depending on the type of transaction). Last package – Status– designed to check the success of data acquisition.

The word “package” has been heard many times in relation to the interface. USB, so it’s time to figure out what it is. Let's start with the package Token:

Packages Token there are three types:

Setup

That's why I told this..) Depending on the type of packet, the field value PID V Token package can take the following values:

Token package type OUT – PID=0001
Token package type IN – PID = 1001
Token package type SETUP – PID = 1101
Token package type SOF – PID=0101

Let's move on to the next component of the package Token– fields Address And Endpoint- they contain USB device address and endpoint number, which is intended transaction.

What a field CRC- This check sum, this is understandable.

There is another important point here. PID includes 4 bits, but during transmission they are supplemented by 4 more bits, which are obtained by inverting the first 4 bits.

So, next in line - that is, a data packet.

Everything here is basically the same as in the package Token, only instead of the device address and endpoint number, here we have the transmitted data.

It remains for us to consider Status packages and SOF packages:

Here PID can take only two values:

The packet was received correctly - PID=0010
Error while receiving packet - PID = 1010

And finally packages:

Here we see a new field Frame– it contains the number of the transmitted frame.

Let's look at the process of writing data to a USB device as an example. That is, consider an example of the structure of a recording frame.

The frame, as you remember, consists of transactions and has the following form:

What are all these transactions? Let's figure it out now! Transaction SETUP:

Transaction OUT:

Similarly, when reading data from a USB device, the frame looks like this:

Transaction SETUP we have already seen, let's look at the transaction IN 😉

As you can see, all these transactions have the same structure as we discussed above)

In general, I think that’s enough for today 😉 This is quite a long article, I hope we’ll try to implement the USB interface in practice in the near future!

There are currently several types of connectors USB(Universal Serial Bus) which come in three versions - USB v1.1, USB v2.0 And USB v3.0. Version v1.1 is practically not used due to the too low data transfer speed (12 Mbit/s), so it is used only for compatibility. The second version of USB 2.0 now dominates the market. Majority modern devices support this version, which provides an information exchange speed of 480 Mbit/s, which is equivalent to a copy speed of 48 MB/s. However, due to non-ideal implementation and design features, in practice the actual speed rarely exceeds 30-33 MB/sec. Many hard drives are capable of reading information at 3-4 times faster speeds. The USB v2.0 connector is a bottleneck that slows down the operation of modern drives. At the same time, for mice, keyboards and some other devices this does not matter much. The third version of USB v3.0 is marked in blue, which indicates that it belongs to the latest generation. The bandwidth of the third version of USB provides a speed of 5 Gbit/s, which is equivalent to 500 MB/s. Taking into account the fact that modern hard drives have a speed of 150-170 MB/sec, the third version of USB has a large reserve of data transfer speed.

Structurally, USB 1.1 and 2.0 versions are fully compatible with each other. If one of the connected parties supports version v1.1, then data exchange will occur at a reduced speed, and operating system will display the message: “The device can run faster,” which will mean that the computer is using a fast USB 2.0 port, and the connected device version 1.1 is slow. Compatibility between USB 2.0 and 3.0 looks a little 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 USB v3.0 cables and devices have additional pins that allow you to increase the speed of the interface.

USB power

Any USB connector is powered by a voltage of 5 V and a current of 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(phones, players, flash drives, memory cards) will not cause problems, and large and massive equipment is powered from 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 the most widespread and is the most recognizable among the 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 without losing integrity. Although the cross-section of the connector is rectangular, it is protected against incorrect connection, so it’s impossible to stick it in reverse side. However, it is quite large in size, so it is not suitable for portable devices, which has resulted in the creation of smaller modifications.

The USB type B connector is less popular. All modifications of type B, including Mini and Micro, have a square or trapezoidal shape. The traditional full-length Type B is the only type that has a square cross-section. Due to its rather large size, it is used in various peripheral and large-sized stationary devices (scanners, printers, sometimes ADSL modems). Typically, manufacturers of printers or multifunctional devices rarely include such a cable in their products, so the buyer has to purchase it separately.

Mini USB 2.0 Type B

The reason for the appearance of tiny Mini USB Type B connectors was the abundance of miniature devices on the market. And the appearance of portable hard drives ensured their real mass popularity. Unlike large connectors with 4 pins, Mini USB Type B has five pins, however, one of them is not used. Unfortunately, miniaturization has had a negative impact on reliability. During operation, after some time the Mini USB connector begins to loosen, although it does not fall out of the port. At this time, 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 being replaced by a more advanced modification of Micro USB.

The Micro USB type B connector is a modified version of the previous type Mini USB type B and has very miniature dimensions, which allows manufacturers to use it in modern technology with a small thickness. Thanks to the improved fastening, the plug sits very tightly in the socket and does not fall out of it. In 2011 this type connector has been approved as a single standard for charging for smartphones, phones, tablets, players and other portable equipment. This solution allows you to charge your entire fleet of electronics using one cable. The standard is showing growth trends and it can be assumed that in a few years almost all new devices will be equipped with it. Type A is used extremely rarely.

USB 3.0 Type A

The USB v3.0 standard provides significantly higher data transfer speeds. Additional contacts, which made it possible to increase speed, led to a change in the appearance of almost all USB connectors of the third version. However, type A has not changed in appearance, except for the blue color of the core. It means that backward compatibility saved. In other words, a USB 3.0 type A device can be connected to a USB 2 port and vice versa. This is the main difference between the connector and other version 3.0 connectors. Such ports are usually found in modern laptops and computers.

USB v3.0 type B is used in medium and large high-performance peripheral devices - NAS, as well as in stationary hard drives. The connector has undergone major changes, so it cannot be connected to USB 2.0, in particular to USB 2.0 type B. Cables with such connectors are also not often sold.

Micro USB v3.0 is the successor to the “classic” Micro USB connector and has the same characteristics - compactness, reliability, high-quality connection, but at the same time provides higher data transfer speeds. Mainly used in modern external ultra-fast hard drives and SSDs. It is becoming increasingly popular. The connector largely duplicates Micro USB version 2.

Micro Difference USB and Mini USB.

Users sometimes confuse Mini USB connectors with Micro USB connectors, which are really similar. The main difference is that the first one is slightly larger in size, and the second one has special latches on the back side, which make it easier to distinguish these two types of connectors. In other respects they are identical. Today there are many devices with these types of connectors, so it is preferable to have two different cables.

Nowadays, any phone or computer user is familiar with the USB interface. Thanks to it, it becomes possible to connect various devices among themselves, transfer data. It also charges many phones. USB has gained great popularity due to its versatility.

What is USB

When creating the interface, the developers set the initial task of connecting a computer and a phone. At the moment, connecting any two devices can be done without a computer. The abbreviation USB stands for Universal Serial Bus and is translated as a universal serial bus. It has power line, which is located among the information transmission lines. The technology allows you to transmit power with a power of 5V, 500 mA. Serial transmission allows you to achieve exchange speed information up to 480 Mbit/s. The combination of these factors led to the great popularity of the interface.

Features, advantages and disadvantages

USB features include ease of use. When connecting the device to a PC, the interface interacts with Plug and Play technology and automatically selects drivers, which makes it much easier to use. Since entering the market in 1996 USB connectors began to appear in any PC specifications, and with its further popularity their number only grew. Nowadays it is difficult to imagine any device without a USB port, because its absence leads to many inconveniences.

Types and specifications

First version came out in early 1996 and had a throughput of 12 Mbit/s and a cable length limit of up to 5 meters.

The next one was 1.1, which was released two years later. It corrected the errors and shortcomings of the first one. This version has become widespread.

Published in the first quarter of 2000 version 2.0 in which the Hi-speed mode appears, increasing throughput to 480 Mbit/s. Now it is the most common and is installed on more than half of PCs.

The following specification is USBOTG, which was created by developers to simplify the connection of peripheral devices without using a computer. For example, you can connect a printer and a video camera. Or connect a USB flash drive to the PDA, if of course the PDA supports OTG standard. The developers were forced to create such a specification because... Lately Users increasingly need to connect devices to each other, but do not have a PC at hand.

In 2008, the newest USB 3.0(sometimes called USB SS), in which the developers increased the maximum throughput and maximum current. To do this, it was necessary to add a couple of contact lines, and only thanks to this the data transfer speed increased to 5 Gbit/s, and the current strength to 900 mA. So that the average user can distinguish the second version from the third, manufacturers began to mark the latest version in blue, which can be easily seen if you look at the port itself.

In 2013, a USB specification with a throughput of 10 Gbit/s called 3.1 was released. This version already uses connectorType-C, which can be connected from either side, just like Apple’s Lightning.

Last one for today version 3.2 was released in 2017 and doubled the data transfer speed to 20 Gbps as two more were used contact lines. Type-C cables currently available support this specification and allow data exchange at such speeds. The interface is planned to be launched to the masses in 2019.

In May 2005, the opportunity arose to create wireless communication With high speed data exchange thanks to the interface Wireless USB.

In 2006, a specification for 2.0 Inter-Chip USB, which simplified the connection of microcircuits. This became possible due to the change in the physical layer of the interface from asynchronous to synchronous. The ability to change speed modes has been removed, electrical protection drivers and connection definition. The bus logic remains unchanged, the interface has a throughput of 480 Mbit/s.

Types and types of connectors

Due to the great popularity of the interface, it received a large number of different connectors and plugs. They are divided into two USB type type A and B and are also divided by size into standard, mini and micro USB.

The first version of the connectors is different low speed only 12 Mbit/s.

The second version was able to exchange data at speeds of 480 Mbit/s. Now this is the most popular variation and it is installed on most devices and PCs. Due to various factors, the actual operating speed is about 30 MB/s, which may negatively affect the work with the latest hard drives, in which the exchange of information occurs much faster. This is the main disadvantage of this connector.

It is marked in blue so that it can be easily distinguished from the second one. The speed of this version is 5 Gbps, which is perfect for HDD latest generation and reveals their full potential.

Also both of these versions can be different sizes. Mini USB is used to connect printers, video and photo cameras and is significantly smaller than a regular one.

Connector micro USB the smallest of the entire family. Used in modern smartphones, watches, bracelets and similar devices. The connector has latches that ensure constant contact.

In fact new standard USB 3.1 and the Type-C connector should calm down the mess and restore order. For everything about everything - one single cable: for data transmission, audio, video signals and power supply. The symmetrical Type-C connector is a real blessing for mobile device users who are tangled in wires. A USB standard 3.1 allows, for example, to play video from a tablet on a TV while mobile device charging.

Just the transition to new specifications poses additional difficulties for manufacturers, which is why sellers and buyers immediately become despondent. Companies cannot be blamed for lack of interest: after entering the market MacBook Pro(2015), many manufacturers have introduced products that support the new USB 3.1 standard with a Type-C connector, including devices such as motherboards, monitors, external drives and smartphones. Yes, connector USB Type-C equipped with LG G6, as well as HTC 10 and Samsung Galaxy S8, which connects to the docking station via a universal connector, turning into a full-fledged personal computer. But a new form does not always mean new functions: for example, Type-C in the Huawei version does not support USB 3.1, but for fast charging generally uses its own technology.

Old devices are a hindrance to new standards

Variety of connectors
Many USB devices still come with one of the old connectors. Type-C should replace them all

Technical breakthroughs always take a very long time if there is a large fund old technology. Keyboards, mice, external drives, webcams, digital cameras, USB flash drives - millions of these devices still require support for older versions of USB. The problem could be temporarily solved by using universal adapters, but completely new devices with old USB ports are still being released.

And since a regular USB cable is not so easy to distinguish a host from a client device, it still requires two different types connectors. That's why external hard drives often come with Mini-A connectors, while printers come with typical quad connectors. Type-B connectors. Sooner or later, USB Type-C should replace not only these connectors - using a cable it would be possible, for example, to connect peripheral devices to a PC without any problems. Moreover, Type-C can send DisplayPort, HDMI and even TRS jacks into oblivion.

Don't be confused: Type-C is not USB 3.1

"Talking" logos
Logos should reflect what functionality the USB connector provides. Unfortunately, not all manufacturers use them

Since the USB consortium approved two other specifications at the same time as the Type-C connector, there is often some confusion in the concepts. Firstly, we have a new Type-C connector with a 2x12 mirror pin layout, making the port insensitive to the orientation of the plug - which means that the problem of “how to plug it in” USB plug Type-A right the first time” will soon be forgotten.
Secondly, along with the new connector, a new USB 3.1 standard has been introduced, increasing the data transfer rate ceiling to 10 Gbps (gross).

Further, USB Power Delivery (USB-PD) is presented in a new, second revision: it implies faster charging of connected devices by increasing power (20 V, 5 A instead of the previous 5 V, 0.9 A). In other words, although USB Type-C, USB 3.1 and USB Power Delivery are often equated, they are not equivalent terms or synonyms. So, there is, for example, a USB 2.0 interface in Type-C format or a USB 3.1 port without support for Power Delivery fast charging.

But that is not all. It is impossible to completely remove the blame for the mess from the consortium, since it abandoned the use of conventional nomenclature: with the advent of USB 3.1, USB 3.0 ceased to exist in the sense that this previous version is now classified as USB 3.1 Gen 1, and the new technology is called USB 3.1 Gen 2. But many USB cables and devices are sold under the name USB 3.1 - without specifying which generation is meant.

The USB Consortium, however, has developed a system of logos to designate USB Type-C connectors so that you can distinguish, for example, a Type-C plug supporting USB 3.1 Gen 1 from a plug supporting USB 3.1 Gen 2 or even old USB 2.0, but first you need to carefully study the logos. It's not uncommon to have to look at the manual to figure out which version you're using - unless, of course, detailed documentation is available. It's not surprising that many manufacturers continue to use the previous name USB 3.0.

Limit values of USB versions
USB 3.1 Gen 2 doubles data transfer speeds and increases current for fast charging

To all this diversity should be added the Thunderbolt 3 interface, developed primarily by Intel and Apple. Thunderbolt from the third version also uses a Type-C connector, but is not entirely compatible with USB 3.1. With active Thunderbolt 3 cables, throughput reaches up to 40 Gbps (gross), four times that of USB 3.1. This not only provides very high data transfer speeds, but will also allow multiple video streams with 4K content to be transmitted over DisplayPort and even use external video cards. Complex technologies require the use of active electronics in cables. USB devices can be connected to the Thunderbolt 3 port, but never vice versa.

Difficult choice of cables

The confusion doesn't stop with standards and versions alone. If previously you could limit your choice to one USB cable with the right types connectors, with USB 3.1 and Type-C it will not be so easy. Here, as in the case of standards and versions, there has now been formed huge drawback information: not all Type-C cables can transmit data, video and supply power. In many cases, it is not clear to users whether a Type-C cable supports Power Delivery fast charging or an alternative mode for video transmission, because logos and markings, as a rule, are simply not there.

Premium motherboards
Currently USB time 3.1 Gen 2 is supported only by select premium motherboards. Among them is Asus Rampage V 10, equipped with two Type-A and two Type-C ports, it costs about 38,500 rubles

It is often impossible to determine whether a cable supports USB 3.1 or just USB 2.0. On the Amazon website, there are very often reviews from upset customers who, after purchasing, discovered that the purchased cable does not support the fast charging technology of their smartphones. Even the designation by some manufacturers, for example, Aukey, of a USB 3.1 Gen 1 cable with Type-C and Type-A ends as a “Type-C to USB 3.0 cable” does not help to get out of this difficult situation at all - this is completely wrong.

If you decide to get a device with a Type-C connector, be sure to make sure that the package includes a cable - only then will all your requirements be satisfied. Equipment supplier for computer equipment Hama, for example, offers several Type-C cables with detailed characteristics, but prices start from 1000 rubles. Buying a Thunderbolt 3 cable will cost even more - you will need to shell out about 2,000 rubles. But all the functions are provided here. If this price is too high, then willy-nilly you will have to rummage through product descriptions and customer reviews about them in search of the right cable.

USB-C: balanced plug

Data transfer, power supply and dialogue between devices - each of the 24 pins of the Type-C plug performs a separate function. It is easy to notice that their arrangement is symmetrical.

Displays, laptops and adapters

To transfer video in one of the alternative modes (DisplayPort or HDMI), that is, for example, from a laptop to a monitor, you should also pay attention to the technical requirements. There are currently several monitors on the market with a USB Type-C connector from LG, Eizo, Acer and HP (for example, Envy 27, about 40,000 rubles). For video output, the DisplayPort standard is almost universally used, which indeed works quite reliably. But if we talk about fast charging, which places special demands on the monitor’s power supply, then in many cases buyers have questions.

Alt mode video
The USB-C connector, for example, like that of the LG 27UD88 (about 38,000 rubles), usually provides reliable video transmission to the monitor, but it does not always provide fast charging with Power Delivery

However, supplying power from the monitor to the laptop is not always necessary. The Asus MB169C+ portable 15-inch monitor (about 15,000 rubles) receives power from the laptop via a fully used Type-C connector.
One way or another, nowadays it more often happens that a laptop with a USB Type-C connector is connected to a monitor via an HDMI or DisplayPort port. In such cases, an adapter is required that converts the video signal and transmits it to the monitor using the desired standard. Such accessories can be purchased from about 1000 rubles. Compared to other cables, choosing adapters is quite simple, because their task is only to convert the video signal without taking into account other features of USB 3.1.

For those interested in a laptop or tablet with a Type-C connector, the choice is currently limited, but great. In addition to MacBook (12 inches) there are hybrids Acer Aspire Switch 10 V (about 25,000 rubles) and Asus T100HA (about 18,000 rubles). And the young Chromebook Google Pixel equipped with two whole Type-C ports (though only of the USB 3.1 Gen 1 standard), but it has not yet gone on official sale in Russia.

Old documentation
Even though the Acer Aspire Switch 10 V only has one Type-C port, the manual lists older types of USB connectors

Probably, it is unlikely that any user will dare to transfer all their peripheral devices to Type-C at once, so most laptop owners will first need a USB 3.1 adapter to transfer data and video signals via a USB Type-A, HDMI or DisplayPort cable. Prices for recommended flexible models start at 2,500 rubles, such as the Icy Box IB-DK4031. Club 3D SenseVision is more expensive - about 6,500 rubles - but it includes HDMI, DVI, USB 3.0 Type-A, 4 USB 2.0 connectors, USB fast charging, as well as jacks for connecting a microphone and headphones.

Less rich in currently choice for desktops: traditionally, motherboard manufacturers introduce new standards in premium models. The only one motherboard with four USB 3.1 Gen 2 ports (two each Type-A and Type-C) is the Asus Rampage V 10, which costs about 38,500 rubles. At least an indication of fast transfer 10 Gbit/s is also located on the panel of interface connectors. One of USB options 3.1 from the bottom price category desktops is MSI X99A SLI (LGA 2011-3) with one Type-A and one Type-C port for about 15,000 rubles.

Universal adapter

Switching to computers with a Type-C connector will require an adapter with different types of ports for the peripherals.

> Club 3D SenseVision (about 6500 rubles)
The adapter is relatively expensive, but is equipped with a large number of ports, including HDMI, DVI, microphone and headphone jacks, as well as four USB port 2.0 and fast charging connector (USB 3.1 Gen 1)

> Icy Box IB-DK4031 (about 2500 rubles)
A simpler version of the adapter with a Type-A connector (USB 3.1 Gen 1), HDMI,
as well as a Type-C connector with Power Delivery for fast charging of external devices.

Benefit from external storage thanks to USB 3.1

Fast memory
USB 3.1 Gen 2 gives many external SSDs, such as the Freecom mSSD MAXX, a significant jump in speed

Of course, network storage with a RAID configuration and external drives, primarily flash memory - solid-state drives and USB flash drives, benefit from the high data transfer speeds of USB 3.1 Gen 2. But for the latter, the availability of USB 3.1 Gen 2 is currently reduced to zero. The offered flash drives from SanDisk, Kingston and Corsair, positioned as USB 3.1, transfer data at a speed of no more than 5 Gbit/s, that is, they belong to the first generation. However, for most flash drives this should be sufficient for now.

As for external solid-state drives, the manufacturers Freecom (mSSD MAXX, about 8,000 rubles) and Adata (SE730, about 9,500 rubles) offer drives with USB 3.1 of the second generation. The first practical tests show that the high-speed interface actually provides significantly more high speeds data transmission. Terramaster offers a housing for network storage D2-310 with two compartments (about 10,000 rubles) with support for USB 3.1 Gen 2, on which high-speed SATA drives in a RAID array should also make a good impression.

Music over USB-C
The score has been opened for the headphone jack on a smartphone: a Type-C to TRS adapter will soon appear as standard

It should be separately noted that memory manufacturers do the best job of specifying versions and standards and are the least likely to leave their customers halfway. The remaining manufacturers must urgently supplement the documentation and properly implement the standards.

Transitioning from one generation of technology to the next has always been a long and often confusing process, but not since the days of VHS and Betamax has there been such confusion as now. Someday, the USB 3.1 / Type-C configuration will really make life easier for everyone - especially users, but for now there are many difficulties to be overcome.

PHOTO: CHIP Studios; Freecom; Stouch; Club 3D; Raidsonic; Acer; LG; Asus; Sabrina Raschpichler

What is USB? Today, probably only the lazy do not know or have heard about this. USB is firmly established in life modern man, and many areas of activity cannot be imagined without it. USB has surpassed all other similar interfaces in popularity that interact with computer peripherals. Almost all electronic gadgets and systems are equipped with USB connectors: computers, phones, tablets, TVs, car radios and many other devices.

USB concept

A technical definition will help you understand what USB is. The official documentation states: USB, Universal Serial Bus - universal serial bus. In essence this is software tool, making a connection for transmitting data between electronic gadgets.

USB has its own symbolic icon in the form geometric shapes: two circles (small and large), a triangle and a square. Three branched lines emerge from the large circle, at the ends of which are the remaining figures.

You can define what USB is, more simple concept. This is the connector to which a device with a plug of the same standard is connected. For example, when USB help To personal computer connects keyboard, mouse, printers. Phones, smartphones, tablets, e-readers, portable hard drives and many other gadgets are connected to exchange information, install various updates, and settings.

Features and Benefits

This interface was developed and introduced at the end of 1994. Hand to the advent of USB Companies such as Microsoft, Intel, Philips and US Robotics have contributed.

Previously, external third-party devices communicated with the PC through such switching means as PS/2, serial and parallel input ports, a separate connector for connecting game controllers, and no one had even heard of what USB was. When developing new gadgets, there was an urgent need to unify switching capabilities. The presentation of the new standard led to increased functionality of the computer and stimulated the development of third-party products with the USB bus.

Today, all PCs and laptops are required to have USB connectors. IN desktop computer Up to 12 USB connectors can be mounted, the laptop has 3-4 inputs. Any modern “self-respecting” gadget has a USB port.

Simplicity and ease of use have become synonymous with USB technology. It allowed interoperability with the "Plug and Play" specification, which implied reliable, fast and user-friendly switching external sources.

USB standardization

Trial specification standards were presented at the end of 1994. Several more versions were released throughout the year, and on January 15, 1996, the USB 1.0 standard was presented. It was characterized by two types of data exchange: a high throughput channel of up to 12 Mbit/s and a low throughput channel of 1.5 Mbit/s. High traffic length USB cable was 3 m, and at low - 5 m. The voltage for connected devices was determined to be 5 V with a maximum current of 500 mA. Up to 127 gadgets could be connected. Moreover, they could all function with different access standards.

In September 1998, work was carried out on the detected errors, the speed was increased to 15 Mbit/s, and USB version 1.1 was launched.

The beginning of 2000 was marked by the release of the USB generation 2.0 interface. A high-speed data processing and transmission mode was introduced. USB 2.0 received three types of bandwidth:

from 10 to 1500 Kbps was used for operation with keyboards, mice and gaming gadgets;
from 0.5 to 12 Mbit/s reserved various video and audio media;
from 25 to 480 Mbit/s worked with hard drives (HDD) and video stream processing.

Additional Specifications

In 2005, USB Wireless technology was developed. Characteristic feature wireless switching with high data transfer rates was announced. Within a radius of 3 meters the speed was about 480 Mbit/s, 10 m - 110 Mbit/s.

Through the joint efforts of Microsoft, Intel, Hewlett-Packard and some others, the USB 3.0 specification standard appeared. This version fully compatible with 2.0. The connectors of the latest specification have a characteristic blue plastic color, unlike the white of the previous version. Specification 3.0 has an additional four switching lines, making the cable slightly thicker and the throughput increased to a stratospheric 5 Gbps. With these parameters, for example, information with a volume of 1 TB can be transferred in approximately 50 minutes. Whereas with standard 2.0 the same volume is transmitted in about 9 hours.

Latest version USB has a higher current - 900 mA. This parameter made it possible to connect a larger number of devices to the connector compared to 2.0.

There is also a USB OTG specification that allows connected devices to unilaterally determine when to be a host and when to be a peripheral.

USB connectors

Type A connects a third-party USB device and a computer. It is on the controller side. When connecting any gadget USB drivers the operating system itself instantly finds it. If there are none, the device is always equipped with a software disk, which includes necessary element installations.

Type B is present on the USB peripheral side. These are mainly scanners, printers or multifunction devices. Both types include several plug/connector configuration options: mini USB and micro USB.

The mini USB connector/plug differs more compact size and is found on earlier versions smartphones, cameras, video cameras, e-books, etc.

The micro USB connector/plug is even smaller in size than the previous version. It is often found in modern smartphones.

Disadvantages of the USB interface

Due to design features, mini USB and micro USB connectors often fail before their service life. This is due to the fact that such connectors are usually found in gadgets that very often have to be connected to a computer or charged (phones, smartphones, PDAs, MP3 players). It is worth noting that USB technology not only allows you to exchange data, but also makes it possible to charge devices through its connection.

The stated throughput of the 2.0 specification of 480 Mbps is not true. This happens because data is transmitted in both directions over a single twisted pair cable. For achievement maximum speed 2 clock cycles are required when exchanging information, which, by the way, is implemented in USB 3.0.