USB 3.0 and USB 3.1 Speeds and Other Characteristics 1

USB 3.0 and USB 3.1: Speeds and Characteristics


The technology Universal Serial Bus (USB) is synonymous with of convenience and efficiency, after all, this is a standard that allows the interconnection of devices of the most varied types. However, there are increasingly more devices that work with large volumes of information and, consequently, in need of greater speed in data transmission. It is at this point that comes in the standard USB 3.0, also called SuperSpeed USB.

In the next lines, you will learn about the main characteristics of technology, as well as you will seethe variation of USB 3.1 capable of transmitting data up to two times faster than the USB 3.0.

There’s more: the final part of the text presents details of the USB-C, the new pattern of connection that, by being convertible and compact, should further increase the adoption of technology.

Why the USB 3.0 was created?

The USB technology came in the year 1994 and since then it has been through several revisions. The most popular are the 1.1 and 2.0 versions, with the latter being still quite used. The first one is able to achieve, in maximum transmission rates of 12 Mb/s (megabits per second), while that the second can offer up to 480 Mb/s.

As you can see, the USB 2.0 can be very fast, after all, 480 Mb/s correspond to about 60 megabytes per second. However, the evolution of technology makes a lot faster to be increasingly necessary.

It is not difficult to understand why: the number of high-speed connections to the Internet grows quickly, making people want to consume, for example, videos, music, photos and games in high the definition or resolution. Add to that the fact that each time more common to offer devices such as smartphones and cameras digital that meet those needs. The consequence of not could be another: big data in the hands of a increasing number of people.

With its final specifications are announced in November 2008, the USB 3.0 has emerged to account for this and demand that is to come. It is this or lose space for technologies such as FireWire or Thunderbolt.

To meet this mission, the USB 3.0 has as main characteristic the ability to offer data transfer rates of up to 4.8 Gb/s (gigabits per second). But not it is just so…

What is USB 3.0?

As you saw in the topic above, the USB 3.0 has emerged because the standard needed to evolve to meet new needs. But, what it is exactly that evolution? What the USB 3.0 is different from USB 2.0? The main feature you already know: the speed of up to 4.8 Gb/s (5 Gb/s, rounding), that corresponds to about 600 megabytes per second, ten times more the speed of USB 2.0. Nothing bad, don’t you?

But the USB 3.0 also stands out for the factor power electrical: USB 2.0 works with current up to 500 milliamps and voltage of 5 volts, while the newer version can support 900 milliamps and 5 volts. This means that the USB 3.0 ports are able to supply devices that consume more power, such as certain external hard Drives that with USB 2.0, would require power supplies dedicated.

It is clear that the USB 3.0 also has the features that made the earlier versions are so well-accepted, such as Plug and Play (plug and play), possibility of connection of more than one device on the same port, hot-swappable (ability to connect and disconnect devices without the need to shut them off) and compatibility with equipment in the previous standards.


USB 3.0 connectors

Another aspect in which the standard USB 3.0 differs from 2.0 says respect to the connector. The connectors of both are quite similar, but not the same.

Connector USB 3.0

As you will see later, the cables of the USB 3.0 technology are composed of nine wires, while the USB 2.0 cables use only four. This happens so that the new standard can to accommodate higher rates of data transmission. Thus, USB 3.0 connectors have contacts for these additional wire in the part of the background. If a USB 2.0 device is used, this will use only the contacts of the front connector. The following images show a USB 3.0 connector type A:

You must have noticed that it is possible to connect devices USB 2.0 or 1.1 ports to USB 3.0. This last is compatible with the previous versions. Manufacturers can also make USB 3.0 devices are compatible with the standard 2.0, but, in this case, the speed will be the latter. And of course: if you want to interconnect two devices via USB 3.0 and take advantage of the its high speed, the cable needs to be in the pattern.

USB 3.0 connector B

As is the case in the previous version, the USB 3.0 has also connectors are differentiated to suit certain devices. A of them is the connector of the type B used in the apparatus of larger-sized, as printers or scanners.

In relation to the type B standard USB 2.0, the port USB 3.0 has an area of contacts additional top. This means that it can be connected to so many USB 2.0 devices (that take advantage of only the part bottom) as well as USB 3.0. However, devices 3.0 does not can be connected in ports B 2.0:

Micro-USB 3.0

The micro-USB connector, widely used in smartphones, also undergone modifications: in the standard USB 3.0 — with name micro-USB B —, started to count with an area of additional contact that, in a way, decreases its practicality, but it was the solution found to give account of the extra contacts.

Ports micro-USB-B does not have good acceptance by the industry. Manufacturers, especially smartphones, instead of the standard USB-C (discussed ahead).

On the functioning of the USB 3.0

As you already know, USB 3.0 cables work with nine wires, while the previous standard uses four: VBus (VCC), D+, D- and GND. The first is the responsible for feeding electric, the second and the third are used in the transmission data, while the fourth acts as an “earth wire”.

In the USB standard 3.0, the need for data transmission in high speed meant that, in the beginning, was considered to be the the use of fiber optics for this purpose, but such a feature become the technology guy, and manufacturing more complex. The solution found to give viability the standard was the adoption of more wires. In addition to those used in USB 2.0, there is also the following: StdA_SSRX – and StdA_SSRX+ for data receipt, StdA_SSTX – and StdA_SSTX+ for shipping, and GND_DRAIN as “earth wire” to the signal.

The USB 3.0 connector B can still count with a variation (USB 3.0 B-Powered) that uses a contact to electrical power and other associated with this that serves as “earth wire”, allowing the supply of up to 1000 milliamps to a device.

As to the size of the cables, there is not a set limit, however, testing conducted by some specialized bodies (such as the company Cable Wholesale) recommend a maximum of up to 3 meters to total exploitation of the technology, but this measure can vary according to the techniques employed in the manufacture.

In respect to the transmission of data itself, the USB 3.0 does this work bi-directionally, that is, between devices connected, it is possible to send and receive simultaneously data. In USB 2.0, it is possible to only one type of activity at a time.

The USB 3.0 is also able to be more efficient in the control of the consumption of energy. For this, the host, that is, the machine in the which devices are connected communicates with the devices of way asynchronous, waiting for these indicate the need for transmission data. In USB 2.0, there is a kind of “continuous research”, where the host needs to send signals constantly to know which one you need to traffic information.

Still with regard to energy consumption, both the the host and the connected devices can enter into a state of the economy in times of idleness. In addition, in the USB 2.0, the data transmitted end up going from the host to all attached devices. In USB 3.0, this communication only occurs with the device target.

How to quickly know if a port is USB 3.0?

In certain equipment, especially laptops, it is common to to find, for example, two USB 2.0 ports and one USB 3.0. When there is no description identifying them, how do you know which is which? By the existing color on the connector.

There may be exceptions, of course, but at least good part of the manufacturers to follow the recommendation to identify the USB 3.0 connectors with their plastic part in blue, such as reported previously. In the USB 2.0 ports, in turn, the connectors are black or, less often, white.

USB 3.1: up to 10 Gb/s

In August 2013, the announced the specifications the end of the USB 3.1 (also called SuperSpeed USB 10 Gbps), a variation of the USB 3.0 which aims to provide data transfer rates up to 10 Gb/s (that is, the double).

In theory, this means that connections 3.1 can achieve rates of up to 1.2 gigabyte per second! Do not think that is exaggeration: there are several applications that can take advantage this speed throughout. It is the case of video monitors that are connected to the computer via USB port, for example.

To be able to rates so high, the USB 3.1 doesn’t make use no artifact physical more elaborate. The “secret”, essentially, is in the use of a method data encoding is more efficient and that, at the same time, does not make the technology significantly more expensive.

It is worth mentioning that the USB 3.1 is compatible with connectors and cables earlier specifications, as well as with devices based on those versions.

Noteworthy is also the aspect of the power electrical: thanks to a specification called USB Power Delivery, a single port USB 3.1 can provide up to 100 watts (current up to 5 amps and voltage of up to 20 volts) provided that a suitable cable is used. Video monitors and External hard drives are examples of devices that can take advantage of this feature, eliminating sources dedicated.

USB connector-C (USB type C): the use of the two sides

In December 2013, the announced another novelty for the version 3.1 of the technology: a connector called USB Type-C(USB type (C) or, simply, the USB-C. The standard was finalized inAugust of 2014 and has as main attraction the adoption of a plug is reversible: the USB connector-C can be embedded any side in the USB input.

You know those situations where you try to fit cables or usb sticks in a way, note that you did something wrong, try to again and only then hit? Who never went through this? With the new connector, the problem is in the past. Turn it up or cheap, either: the connection will work in any way.

Another advantage of the USB-C is in its reduced dimensions: the connector has only 8.4 mm wide by 2.6 millimeters of height. With this size, your deployment on tablets, smartphones and notebook sultrathin, for example, is facilitated.

By be prepared to work with the USB 3.1, the USB connector-C it can also handle up to 100 watts — the supply of power is up to 3 amperes in the cable standard and 5 amps in the connector itself. Thus, a single cable can be used both for data traffic and to electric power certain devices.

Such evolution comes at a price: the connector type C is not compatible with the ports of the standards earlier, except by the use of adapters. It is important to to point out, however, that the USB 3.1 can use the connectors already exist before their emergence, but if subjecting the limitations of these.

A USB connector-C standard has up to 24 pins (12 in each face). That is why it is possible to fit it of any side. Four pairs of pins respond by electrical power and grounding, the other four for transmissions of high-speed. Two pairs remain buses for backward compatibility with the USB 2.0 (although only a can be implemented to this end), the other two help in the detection of the orientation of the connector.

Another interesting feature of the USB-C is the Alternate Mode (in free translation, Alternate Mode). With the feature, manufacturers can create additional functionality for cables and entries in the default. Similarly, the USB type C also can be used in conjunction with other technologies.

An example comes the VESA (Video Electronics Standards Association). The entity compatibilizou the latest versions of the technology DisplayPort with USB-C. Thus, a device (such as a laptop) that you have an entry that matches both standards (USB and DisplayPort) you can stream videos to a TV or monitor in 4K resolution or higher.

The USB-C has begun to reach the market in the last quarter of 2014.


The USB 3.0 and USB 3.1 offers a series of advantages, but this it does not mean that the 2.0 version of the technology will be abandoned promptly: there are still many devices that are well met by this specification, the reason for which will be common in the next few years to find motherboards,laptops and the like that offer the two types of doors.

It is expected, however, that, on account of its advantages, the USB-C help the faster versions of the technology to become standard on the market.

USB 3.0 and USB 3.1 Speeds and Other Characteristics 1