The USB port is a standard cable connection interface for personal computers and consumer electronics devices. The abbreviation USB stands for Universal Serial Bus, an industry standard for transmitting digital data over short distances.

is a standard cable connection interface for personal computers and consumer electronics devices. The abbreviation USB stands for Universal Serial Bus, an industry standard for transmitting digital data over short distances. USB ports allow devices to connect to each other and transfer digital data via cable. They can also supply power via cable to devices that need it.

There are both wired and wireless versions of the USB standard, although only the wired version uses ports and cables.

What can you connect to a USB port?

USB port on TV

Many types of consumer electronics support USB interfaces. These types of equipment are most often used for computer networks:

• USB network adapters.
• broadband and cellular modems for Internet access.
• printers for sharing on a home network.
• To transfer files between computers without a network, USB drives are also sometimes used to copy files between devices.

Using the USB port

Connect two devices directly with one cable, plugging each end into a connector. Some devices have more than one port, but do not connect both ends of the cable to the same device as this may cause a short circuit!

You can connect cables to the USB port at any time, regardless of whether the corresponding devices are turned on or not. Follow the instructions included with your equipment before disconnecting cables. In some cases, unplugging the cable from a running device may cause the task in progress to be canceled in operating systems and data will not be written correctly.

Multiple devices can also be connected to each other using a hub. A USB hub connects to one USB port and contains additional connectors for connecting multiple devices at the same time. If using a hub, connect a separate cable to each device and connect them to the hub separately.

USB-A, USB-B, and USB-C port types

There are several main types of physical markings for such ports:

• USB-B (Type B) . This rectangular connector is approximately 1.4 cm (9/16 inch) long and 0.65 cm (1/4 inch) high and is commonly used on routers, computers, printers and game consoles. USB flash drives usually have version "B" connectors.
• USB-A (Type A): Less common than Type B, Type "A" devices are almost square in shape and are typically used for wired mice and keyboards.
• Micro USB: There are also so-called "Micro" versions of both USB-A and Type "B" - smaller versions than their basic counterparts popular on mobile devices. (Old but now obsolete "mini" versions can also be found on some older devices.)
• USB Type C: Measuring 0.84 cm by 0.26 cm, this new standard is designed to replace both "A" and "B" ports with smaller ports to better support thinner mobile device form factors

To connect a device with one type of port to a device of another type, simply use the correct type of cable with the appropriate interfaces on each end. USB cables are manufactured to support all supported combinations of types and male/female options.

USB versions

USB devices and cables support multiple versions of the USB standard from version 1.1 to the current version 3.1. USB ports have the same physical structure regardless of the supported USB version.

USB port not working?

Not everything goes smoothly when you work with computers. There are many reasons why a connector may suddenly stop working correctly.

USB Alternatives

FireWire cable adapter

USB ports are an alternative to the serial and parallel ports available on older computers. USB ports support much faster (often 100x or more) data transfer rates than serial or parallel.

For computer networks, Ethernet ports are sometimes used instead of USB. For some types of computer peripherals, FIreWire ports are also sometimes available. Both Ethernet and FireWire can offer better performance than USB, although these interfaces do not provide power over the wire.

USB is a serial data interface for peripheral devices in computing

The widely adopted USB 1.0 standard was introduced in November 1996. 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.

USB 2.0

The widely adopted USB 2.0 standard was introduced in November 1996.

As with the USB 1.0 and USB 1.1 specifications, the USB 2.0 specification uses a cable consisting of two pairs of wires to connect peripheral devices: one twisted pair of wires for receiving and transmitting data, and the other for powering the peripheral device.

The supply voltage via the USB bus is 5 V at a current of up to 500 mA. This, of course, is not enough for high-power peripherals such as printers. Therefore, they are equipped with their own power supplies, which are connected directly to an electrical outlet. USB cables are oriented, that is, they have physically different ends “to the device” (Type B) and “to the host” (Type A). It is possible to implement a USB device without a cable, with a “to-host” tip built into the housing.

Computers and laptops manufactured after 2003 typically have USB 2.0 ports.

USB 2.0 devices support three operating modes:

• Low-speed, 10-1500 Kbps (keyboards, mice, joysticks, gamepads)
• Full-speed, 0.5-12 Mbit/s (audio, video devices)
• High-speed, 25-480 Mbit/s (video devices, storage devices)

USB 3.0 interface – SuperSpeed ​​USB standard

The USB 3.0 specification appeared in 2008.

In the USB 3.0 specification, connectors and cables are compatible with USB 2.0, and for unambiguous identification, USB 3.0 connectors are made of blue or (for some manufacturers) red plastic.

The USB 3.0 specification increases the maximum data transfer rate to 5 Gbps - which is higher than the data transfer speed of USB 2.0 devices. (maximum 480 Mbit/s)

On July 31, 2013, the USB 3.0 Promoter Group announced the adoption of the next interface specification, USB 3.1, whose transfer speed can reach 10 Gbps. The USB 3.1 Type-C connector is symmetrical.

Types of possible connectors and cables

The number of possible USB 3.0 connectors has increased. The most popular connector that everyone used was USB Type-A of classic size: it is located on flash drives, USB modems, at the ends of the wires of mice and keyboards. Full-size USB Type-B is a little less common: printers and scanners are usually connected with this cable. The mini version of USB Type-B is still often used in card readers, digital cameras, and USB hubs. The micro version of Type-B has become the most popular connector in the world: all current mobile phones, smartphones and tablets (except for the products of one fruit company) are produced with a USB Type-B Micro connector.

In this article I want to cram in as much information as possible related to USB (types, connectors and adapters that currently exist).

USB (Universal Serial Bus) is a serial data transfer interface for peripheral devices in computer technology with built-in power lines. There are two types of connectors/slots for USB:

• Type A
• Type B

Each type is divided into three groups:

• Standard
• Micro

All USB devices have their own version.

USB 1.x and 2.0

Specification 1.0 regulated two types of connectors:

• A – on the controller or USB hub side
• B – on the peripheral device side

Subsequently, miniature connectors were developed for the use of USB in portable and mobile devices, called Mini-USB. A new version of miniature connectors called Micro-USB, was presented USB Implementers Forum January 4, 2007. The appearance is shown in the table (Table 1).

Table 1. Appearance of USB 1.x and 2.0 devices of different types

	Standard	Mini	Micro
Type A
Type B

For USB 1.x, two operating modes are regulated:

• low bandwidth mode ( Low-Speed) - 1.5 Mbit/s
• high throughput mode ( Full-Speed) - 12 Mbit/s

For USB 2.x, three operating modes are regulated:

• Low-speed, 10-1500 Kbps (keyboards, mice, joysticks)
• Full-speed, 0.5-12 Mbit/s (audio, video devices)
• High-speed, 25-480 Mbit/s (video devices, storage devices)

USB 3.x

In the USB 3.0 specification, connectors and cables of the updated standard are physically and functionally compatible with USB 2.0, and for unambiguous identification, USB 3.0 connectors are usually made of blue plastic . The USB 3.0 specification increases the maximum information transfer speed to 5 Gbps - which is an order of magnitude higher than the 480 Mbps that USB 2.0 can provide. Thus, the transfer speed increases from 60 MB/s to 600 MB/s and allows you to transfer 1 TB not in 8-10 hours, but in 40-60 minutes.

On July 31, 2013, the USB 3.0 Promoter Group announced the adoption of the next interface specification, USB 3.1, whose transfer speed can reach 10 Gbps. The appearance is shown in the table (Table 2).

Table 2. Appearance of USB 3.x devices of different types

	Standard	Mini	Micro
Type A
Type B

Examples of adapters and ports (Figure 1-3).

Figure 1 – Types of adapters.

Alternative connection methods, such as USB connectors, are widely used to connect modern devices.

This name is quite common and is translated from English as “universal serial bus”.

All USB connectors are available in three versions.

Characteristic features of the main three versions of USB connectors

First version of USB connectors (1.1). Its characteristic feature is a very low speed, at which all information is transmitted with a long delay.

The transfer speed is 12 Mbit/s. Its main purpose is to be used for interconnecting devices.

Second version of USB connectors (2.0).

Characterized by a data transfer rate of 480 Mbit/s. This corresponds to a speed of 48 MB/s.

The bulk of all modern technical instruments and devices are adapted to use this particular version. It is the most popular and well-known, and therefore is in demand in the electrical goods market.
True, due to many factors, the real speed of this standard does not exceed 30 - 33 MB/s.

Since the latest releases of hard drives, for example, SSDs, are designed to read information at a much higher speed (almost 4 times), this version of the standard delays the effect of new drive models.

This shows the main drawback of the properties of USB 2.0 connectors. But despite this, certain devices are quite compatible with this version of connectors: mice, keyboards, scanners and printers.

Third version of USB (3.0).

This version is characterized by the speed of information transfer – 5 Gbit/s – which is considered a fairly high figure.

This speed corresponds 500 MB/s

This is much higher than the speed of the latest generation hard drives (150 - 170 MB/s).

USB 3.0 connectors are specially marked blue for recognition.

Interface compatibility

If we consider the issue of compatibility of devices that have the connectors presented above, we can state that the first and second versions of USB connectors can be interchangeable with each other.

A particular device that has a USB version 2 connection but accepts a version 1 connection may display a message indicating its ability to perform faster.

Because this computer model is designed to receive information through the second version, the speed of which is higher than the first.

That is, the full speed potential of this device will not be used.
Modern devices that have connectors of the second version can be connected to the third version of USB, and the use of the third version relative to the second is excluded, except for USB 3.0 type A.

Additional contacts create conditions for increasing the speed of the interface - this is a feature of the latest models of cables and devices that have connectors of the third version of USB.

USB power supply

The power for which connected devices with USB connectors are designed is 2,5 W and also 4,5 W (for the third version).

Based on this, USB connectors of all versions require voltage 5 V. Current up to 0,5 Oh, and for the third version - 0.9 A.

Devices such as players, memory cards, phones, flash drives (that is, devices with low power) can be freely connected using such connectors.

And technical means with high power are connected to an external electrical network.

Connector types

The second and third versions of connectors are distinguished by size: Mini USB (small sizes), Micro USB (even smaller sizes); and also by types: A, B.

A reliable connector whose main characteristic is the ability to withstand more than one connection without losing its integrity.

The cross-section of the connector has a rectangular shape, which creates additional protection when connecting.

Its disadvantage is its large size, and all modern devices are portable, which influenced the development and production of connectors of a similar type, but of a smaller size.

USB 2.0 Type A was introduced in the nineties and is currently still the most used.

A significant number of low-power devices have it: keyboard, mouse, flash drive and others.

USB connector version 2.0 type B.

We mainly find its application in stationary devices of large dimensions. These include scanners, printers, and less commonly ADSL modems.

It is rare, but it still happens that cables of this type are sold separately from the equipment itself, because they are not part of the technical device kit. Therefore, check the complete set of devices.

Connectors of this type are not as popular as type A connectors.

The square and trapezoidal shape is inherent in all type B connectors.

These include both Mini and Micro.

The peculiarity of the cross-section of type “B” connectors is their square shape, which distinguishes it from other types.

Mini USB connectors of the second version, type B.

The name of this type of connector indicates that it has very small dimensions. And this is not surprising, because the modern market increasingly offers miniature goods.

Thanks to the use of personal hard drives, card readers, players and other small devices, USB Mini connectors related to type B have become very popular.

It should be noted that such connectors are unreliable. It becomes loose with frequent use.

But the use of USB Mini Type A connector models is extremely limited.

Micro USB 2.0 type B connectors.

Micro USB connector models are more advanced than Mini USB models.

This type of connector is incredibly small in size.

Unlike the previous mini types presented, these connectors are very reliable with their fastenings and connection fixation.

The Micro USB 2.0 connector type “B” has been recognized in its qualities as uniform for universal use for charging all portable devices.

What will happen over time, when all manufacturers begin to produce equipment adapted specifically to such connectors. It probably won't take long to see it.

But this decision was already made in 2011 by all modern manufacturers, although the Micro USB 2.0 type “B” connector is not yet present on all devices.

USB third version type A connectors.

USB 3.0 connectors have greater speed for information transfer due to additional contacts.

With such changes, feedback compatibility is still maintained. Its use has been established in computers and laptops of the latest generation.

USB connectors third version type B.

The third version of USB type “B” connectors are not suitable for connecting USB connectors of the second version.

It is used in the operation of peripheral devices with medium and large productivity.

Micro USB 3.0.

Modern high-speed external drives, as well as SSD-type drives, are basically all equipped with a connector that is characterized by a high speed of information exchange.

It is increasingly occupying a leading position due to the fact that it has very high-quality connections.

The connector is easy to use due to its compact size. Its predecessor is considered to be a Micro USB connector.

The main differences between Micro and Mini USB connectors

At first glance, these connectors are very similar. Indeed, most of the characteristic features of the basic parameters of these species coincide.

But upon closer inspection, you can notice the following differences:

1. The USB Mini connector is larger than the USB Micro connector.
2. The presence of special-purpose latches on the back side of the USB Micro connectors.

Many users have already become convinced that it is most convenient to have not just one type of connector, but several, because different types of devices have different types of USB connectors.

Unfortunately, device manufacturers have not yet come to a single standard, and most likely will not come for a long time, because each type of USB connector has its own purpose.

In fact, the new USB 3.1 standard 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. And the USB 3.1 standard allows, for example, to play video from a tablet on a TV while the mobile device is charging.

Just the transition to new specifications poses additional difficulties for manufacturers, which is why sellers and buyers immediately become despondent. The company cannot be blamed for a lack of interest: after the MacBook Pro (2015) entered the market, many manufacturers 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. Thus, the LG G6 is equipped with a USB Type-C connector, as well as the 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, and generally uses its own technology for fast charging.

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 stock of 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 cannot easily distinguish between a host and a client device, it still requires two different types of connectors. That's why external hard drives often come with Mini-A connectors, while printers come with typical quad-shaped 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 mirror arrangement of 2x12 pins, making the port insensitive to the orientation of the plug - which means that the problem of “how to plug in a USB Type-A plug the first time” will be available very soon forget.
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. The consortium cannot be completely blamed for the mess, since it has moved away from using the usual 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 newly introduced 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 they are referring to.

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 the old USB 2.0, but for starters logos need to be examined carefully. It's not uncommon to have to look at the manual to figure out which version you're using—assuming detailed documentation is available, of course. 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 you to transfer multiple video streams with 4K content over DisplayPort and even use external graphics 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 it was possible to limit the choice to one USB cable with the required types of connectors, with USB 3.1 and Type-C it will not be so easy. Here, as in the case of standards and versions, there is currently a huge lack of 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 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. Computer hardware supplier Hama, for example, offers several Type-C cables with detailed specifications, but prices start at 1,000 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 the 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 Google Pixel Chromebook is 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.

The choice for desktops is less rich at the moment: traditionally, motherboard manufacturers introduce new standards in premium models. The only 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 the indication of fast transfer of 10 Gbit/s is also on the panel of interface connectors. One of the USB 3.1 options from the lower price category of desktops is the 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 2.0 ports and a 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 does indeed provide significantly higher data transfer rates. Terramaster offers a two-bay D2-310 network storage enclosure (about 10,000 rubles) with support for USB 3.1 Gen 2, which should also make a good impression on high-speed SATA drives in a RAID array.

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