USB 2.0 and USB 3.0 are the different specifications of the USB where the USB 2.0 specification was released before the USB 3.0. The latter version USB 3.0 has many advantages over USB 2.0 as it is the successor of the version of 2.0. The most crucial difference lies within the speed of the data transfer, where the USB 2.0 transfers at the rate of the 480 Mbps. On the other hand, the USB 3.0 support the speed up to 5 Gbps.
There are several more differences between the USB 2.0 and USB 3.0 such as in the physical structure of the interface, connectors, type of communication and number of wires etcetera, which we will discuss in the article.
Content: USB 2.0 Vs USB 3.0
|Basis for comparison||USB 2.0||USB 3.0|
|Physical structure||Black block inside the USB port.||Blue block inside the USB port.|
|Data transmission rate||480 Mbps||4800 Mbps|
|Type of communication||One-way||Two-way|
|Amount of power delivery||500 mA||900 mA|
|Compatibility||Will work with USB 3.0 port||USB 3.0 is entirely backward compatible.|
|Number of wires||4||9|
|Length of the cable||5 meters||3 meters|
|Standard-A connectors colour||Grey||Blue|
|Standard-B connectors||Small||Bigger in size|
|Signalling technique||Polling mechanism||Asynchronous mechanism|
|Price||Less expensive||Costly comparatively.|
Definition of USB 2.0
USB 2.0 was introduced in the year 2000. It is a successor of USB 1.1 and provides more functionalities and speed as compared to USB 1.1. USB 2.0 can deliver the maximum transfer speed of 480 Mbps. However, practically the effective calculated throughput can be approximately 280 Mbps. It was backward compatible with the USB 1.x series.
USB 2.0 Standard
- A plug and receptacle – Standard-A USB plug is injected into a USB host or a hub and transfer both power and data.
- B plug and receptacle – Standard-B USB usually plugs into a bigger device like a printer.
- Micro – USB 2.0 (Micro-A, Micro-B and Micro-AB) plug and receptacle – Micro-USB connectors conveys both power and data. It also supports USB On-The-Go. These can be used in small portable devices, like smartphones, digital cameras, GPS devices and more.
Working of USB
There are four-wire cable interface used for USB. Two wires are intended to transmit and receive data, and the rest two are used for power and ground. The USB can be powered by itself, or a hub, host. Each USB end has either of the two connector types, one for the upstream communication and the other is for the downstream. The maximum length of the cable can go up to 5 meters.
There are four types of data transfer mode for USB that are control transfer, bulk data transfer, isochronous transfer, and interrupt data transfer.
- Control Transfer – The function of the control transfer is to configure devices and read the status information.
- Bulk Transfer Mode – It is used for delivering the huge quantities of data and implements three phases: token packet, the data packet and at last handshake packet. In this transfer, the data is protected with the help of error-detecting codes.
- Isochronous Transfer Mode – This mode is considered as the best effort mode as it uses packets with at most 1024 bytes of size. There is no assurance of the delivery of the data and it also does not conduct the handshake phase.
- Interrupt Transfer Mode – It is used for periodic transfer of the data — for example, a mouse or keyboard. There is a bounded latency associated with this mode, and it also includes three phases, token, data and handshake in an order.
Definition of USB 3.0
USB 3.0 is an updated version of USB 2.0 which provides higher data transfer rates up to 5 Gigabits per second. The speed provided by USB 3.0 could make a 25-gigabyte file to be transferred in more or less 70 seconds. On the other hand, when it comes to USB 2.0, it takes 14 minutes for transferring the same file. There are several advantages of USB 3.0 over USB 2.0, which are presented when devices like storage devices, video cameras, hard drives are connected to it instead of printer or keyboard.
USB 3.0 Standard
- Standard A connectors – Except for the additional contacts these are quite similar to the USB 1.1 and USB 2.0. Many of the port cluster connectors are labelled by blue colour and compatible with any USB cable.
- Series B connectors – These exist in two types – Standard-B and Micro-B. Micro-B was devised for the mobile devices but is used by portable and desktop USB 3.0 hard drives.
- Micro-AB and Micro-A are also a part of USB 3.0 designs, but these are not prevalently used.
Key Differences Between USB 2.0 and USB 3.0
- The USB 2.0 port contains black block inside it. On the contrary, USB 3.0 has a blue block inside the USB port.
- The transfer rate provided by the USB 2.0 is 480 Mbps while USB 3.0 can deliver the data at a speed of 5 Gbps. However, the practical speed of USB 3.0 is approximately 3 Gbps.
- The communication provided in USB 2.0 is one-way that is one can either send or receive the data at a time. In contrast, USB 3.0 enables two-way communication where 2 unidirectional data paths are established one for sending the data and the other for receiving the data.
- USB 2.0 can supply 500 mA of the electricity to the connected devices. As against, USB 3.0 can deliver 900 mA of power.
- There is 4 number of wires attached to the USB 2.0 whereas USB 3.0 has 9 wires.
- The length of the USB 2.0 can be 5 meters. Conversely, the cable length of the USB 3.0 can be at a maximum of 3 meters.
- Signalling technique used in the USB 2.0 is known as polling where data be either send or receive at a time. On the other hand, the USB 3.0 uses asynchronous mechanism for signalling which allows the simultaneous transfer of data (i.e., sending and receiving).
- The cost of the USB 3.0 cable is greater than that of the USB 2.
In a nutshell, the USB 3.0 has several advantages over the USB 2.0 as it is an enhanced version of USB 2.0.