Distinguish between USB 3.0 and USB 2.0

USB 3.0 is a USB standard with better speed and more efficient power management than USB 2.0. USB 3.0 can be backward compatible with USB 2.0 devices. However, the data transfer speed will be limited to the speed of USB 2.0 when USB 3.0 interacts with USB 2.0 because USB 2.0 has a lower speed. In 2014, a new standard, USB 3.1, was announced and is expected to be released at the end of 2015.

1. Comparison table of USB 2.0 and USB 3.0

USB 2.0 on the left, USB 3.0 on the right

Criteria	USB 2.0	USB 3.0
Launched	July 2000	November 2008
Speed	High Speed ​​(HS) 480 Mbps (Mb/s)	10 times faster than USB 2.0 speed. Super Speed ​​(SS), 4.8 Gb/s
Signal transmission mechanism	The sequential mechanism means data can be sent or data can be received (Half duplex - half-duplex transmission)	Synchronous mechanism means being able to send and receive data at the same time (Full duplex - full duplex transmission)
Price	USB 2.0 is cheaper than USB 3.0	USB 3.0 is more expensive than USB 2.0
Number of cables	4	9
Standard connection A	Grey	Green
Standard connection B	Smaller size	There is more room for wires
Connector	- USB Type A: These connectors are technically known as USB 2.0 standard A and are rectangular USB connectors that you will find on most non-portable devices. The USB 2.0 Type A connector is physically compatible with connectors from USB 3.0 and USB 1.1. - USB Type B: These connectors are technically known as USB 2.0 standard B and are square except for a small notch on the top. USB 2.0 Type B connectors are physically compatible with USB 3.0 and USB 1.1 Type B receptacles, but USB 3.0 Type B connectors are not backward compatible with USB 2.0 Type B receptacles. - USB Micro-A: These connectors , especially the plug, looks like a miniature version of a USB 2.0 Type A connector. The USB 2.0 Micro-A plug is compatible with both USB 2.0 Micro-AB receptacles and USB 3.0 Micro-AB receptacles. However, the new USB 3.0 Micro-A connector will not fit into a USB 2.0 Micro-AB socket. - USB Micro-B: These connectors are small and rectangular, but the two corners on one side are slightly slanted instead of perpendicular. The USB 2.0 Micro-B plug is compatible with both USB 2.0 and USB 3.0 Micro-B receptacles, as well as Micro-AB. Newer USB 3.0 Micro-B plugs are not backward compatible with Micro USB 2.0 receptacles. - USB Mini-A: These connectors are small and shaped almost like a rectangle with one side very rounded. USB 2.0 Mini-A plugs are only compatible with USB 2.0 Mini-AB receptacles. - USB Mini-B: These connectors are small and roughly rectangular in shape with noticeable indentations on the wide side. The USB 2.0 Mini-B connector is compatible with USB 2.0 Mini-B and USB 2.0 Mini-AB receptacles.	- USB Type A: These connectors, officially called USB 3.0 standard A, are simple rectangular USB connectors, like those on a flash drive. USB 3.0 Type A plugs and receptacles are physically compatible with USB 2.0 plugs and receptacles, as well as USB 1.1. USB Type B: These connectors, officially called USB 3.0 Standard B and USB 3.0 Powered-B, are square with a large groove on top and are often found on printers, as well as many large devices. other. USB 3.0 Type B plugs are not compatible with Type B receptacles from older USB standards, but plugs from those older standards are compatible with USB 3.0 Type B receptacles. - USB Micro-A: USB 3.0 connector Micro-A is rectangular in shape, divided into two parts, and is found on many smartphones and similar mobile devices. USB 3.0 Micro-A plugs are only compatible with USB 3.0 Micro-AB receptacles, but older USB 2.0 Micro-A plugs will work in USB 3.0 Micro-AB receptacles. - USB Micro-B: USB 3.0 Micro-B connectors look very similar to Micro-A connectors and are found on similar devices. USB 3.0 Micro-B connectors are only compatible with USB 3.0 Micro-B receptacles and USB 3.0 Micro-AB receptacles. Older USB 2.0 Micro B plugs are also physically compatible with both USB 3.0 Micro-B and USB 3.0 Micro-AB receptacles.

When a USB 3.0 is plugged into a USB 2.0 port, what will the data transfer speed be?

2. What are USB 3.0 and USB 2.0?

Developed in the 1990s, Universal Serial Bus, or USB for short, is a wired connection standard in computers. USB is used for the purpose of connecting devices (phones, tablets, cameras, camcorders, music players) to the computer. Devices such as smartphones, PDAs, tablets, and handheld gaming devices (such as PS3, PSP.) can connect to computers using USB ports.

Released ten years ago in 2008, USB 3.0 is the third official version of the USB standard. It upgrades USB 2.0, which was released in 2000 and has a relatively slow transfer speed of 480 Mbit/s. USB 2.0 can load 500 mA at 5V. USB 3.0 has significantly more power load than USB 2.0, up to 900 MA at 5V voltage and data transfer rate of 5 Gigabits per second (Gbit/s). And more than 5 years later, in 2014, USB 3.1 was announced and expected to launch at the end of 2015.

3. What is USB 3.1?

USB 3.1 Gen 1

USB 3.1 Gen 1 (USB 3.1 Gen 1) is similar to USB 3.0. In fact, with the release of USB 3.1 Gen 1, all existing USB 3.0 ports were renamed to USB 3.1 Gen 1. Therefore, cables and devices now support USB 3.1 Gen 1. This has made some changes like the USB Type C connector on the new MacBook Pros.

Despite the new name, data transfer and power loading capabilities remain the same as USB 3.0. USB 3.1 Gen 1 supports speeds up to 5 Gbit/s or 625 MB/s and loads up to 900 mA at 5V. The USB 3.1 Gen 1 connector looks like a USB 3.0 A connector, with a blue color on the inside. Unlike Gen 2, Gen 1 has more than one type of connection port. It has a bulky Type B (also known as printer) connector as well as a slim Micro-B connector on top. These ports are not capable of supporting full power for USB 3.1 Gen 2.

USB 3.1 Gen 2

This standard was released in July 2013, USB 3.1 Gen 2 has a transfer speed of 5 Gbit/s like USB 3.1 Gen 1 and allows maximum speeds of up to 10 Gbit/s (1.25 GB/s). S). Gen 2 also has a higher power load capacity, 5000 mA at 20V voltage via USB Type C connection port.

Only the USB Type C connection port can fully handle the power and bandwidth of Gen 2. However, it also has the limitation of short cable length. Additionally, devices and cables that support the newer Gen 2 standard are less common.

A few things about USB Type C (USB-C)

 

USB Type C (USB-C) is not only a connection port but also a USB standard. Although the structure of the connection port makes some features of USB 3.1 Gen 2 better, it does not determine the transfer speed and power load capacity itself, so you can use the device instead. at both ends of the cable to determine this information. But because the documents are not specific, some buyers often confuse USB 3.1 with USB-C. However, if you buy a quality cable with USB Type C connectors on both ends, it will support all USB 3.1 Gen 2 features.

USB-C is an impressive connection port. It replaces all previous connectors, creating a universal, robust connection capable of safely transmitting up to 5,000 mA at 20V.

4. USB 3.0 has more outstanding features than USB 2.0

1. Transmission speed: USB 2.0 has a transfer speed of 480 Mb/s while USB 3.0 has a transfer speed of 4.8 Gb/s - 10 times faster than USB 2.0.

1. Additional number of wires: The number of wires in USB 3.0 has doubled, from 4 wires to 8 wires. Additional wires require more space in both the cabling and connection sections, so new connection styles have been designed.

1. Power consumption: USB 2.0 provides 500 mA while USB 3.0 provides up to 900 mA. USB 3.0 devices provide more power when needed and are more energy efficient when the device is connected but inactive.

1. More bandwidth: Instead of processing data in one direction, USB 3.0 uses two unidirectional data paths, one to receive data and one to transmit data, whereas USB 2.0 can only process data in one direction.

1. New feature: A new feature has been added to USB 3.0 (using the NRDY and ERDY packages) to notify a device that is out of sync with the host.

When data is transferred through the USB 3.0 device, cable, and connection, the server sends a request to choose how to connect the devices. These devices can be accepted for connection or ejected.

If accepted, the devices will send data or receive data from the server.

If there is a lack of buffer space or data, it will respond with a Not Ready (NRDY) signal - a signal to notify the server that it cannot process the request. When the device is ready, it sends an Endpoint Ready (ERDY) to the host which will then re-establish connections.

5. Distinguish between USB 2.0 and USB 3.0

Normally, USB 2.0 standard pins are black, while USB 3.0 standard pins are blue.

From left to right: Micro USB Type AB, Micro USB Type B, USB 2.0 Type A, USB 2.0 Type B, USB 3.0 Type A, USB 3.0 Type B, USB 3.0 Type Micro B, Mini USB Type A.

6. Backwards compatibility

The USB 3.0 standard is backward compatible with the USB 2.0 standard. However, the speed is limited because the USB 2.0 port has a lower speed.

However, USB 3.0 type B will not be compatible with USB 2.0 and devices using the USB 2.0 standard. This means that USB 2.0 and USB 1.1 peripherals cannot connect on USB 3.0 Type B, although USB 2.0 can be used to connect to USB 3.0 devices if is within the USB 2.0 standard speed range.

7. How to know if you are using USB 2.0 or USB 3.0?

If your device has a blue port that indicates USB 3.0 but the data transfer speed is not faster, you may actually be using USB 2.0. Luckily, there are a few ways to tell if this is the case, starting with Windows.

Windows

On Windows, you can use a free application called USB Device Tree Viewer. Unlike the built-in Windows Device Manager, it displays the USB standard of connected peripherals.

1. Download USB Device Tree Viewer but don't connect your USB peripheral yet.

2. Unzip the downloaded application and run it, it will show you all the USB peripherals connected to your computer's USB port.

3. Now, plug in the USB peripheral you want to test. The new peripheral will appear in the tree view and you can easily identify it.

4. On the right, complete details about the USB peripheral are displayed. In short, USB Version will display the exact USB specifications. Demanded Current will confirm that.

In this example, the author has plugged in a USB video capture card. The manufacturer named the peripheral "MACROSILICON USB 3.0 Capture". But the truth is that this is a much slower USB 2.0 device.

Linux

On Linux, you can use the command to find out the USB specifications of the connected device.

1. The USB peripheral is not connected. Open the command line. List available USB peripherals with:

lsusb

2. Plug in the new USB peripheral and run the same command. By comparison, you can identify the USB device.

3. Now, run the lsusb command along with bcdusb:

sudo lsusb -v | grep -iE "Bus|^Device Desc|bcdusb"

The output will show the actual specifications of the USB peripheral. In this case, the device named "USB 3.0" by the manufacturer is actually just USB 2.0.

Check your USB devices and ports and ensure they comply with the rated USB specifications before the return period ends. Otherwise, you will be stuck with slow devices!