What is USB?

By: bella


USB stands for ‘Universal Serial Bus’. USB is a standard developed in the 90’s for the manufacturers of connectors, cables which are devised for the data exchange in computer and other electronic devices like Digital video camera. This standard become too popular in the computer world and is mostly followed in connection with all peripheral devices like mouse, keyboards, printers, digital video camera, external drives etc.
Internal structure of USB: USB cable consists of four shielded wires in which two of them are dedicated for power supply, one for +5V and the other for ground. And a twisted pair of cable which used for data transmission.
Chronological development of USB:
USB 1.0 was launched in January 1996 which delivers data transmission speed 1.5 M bits/sec “Low speed” and 12 M bits/sec “High speed”. Latency for transmission of 1 bit in both High speed and Low speed mode is 1 msec. Twisted pair of cables is used to reduce noise and crosstalk. According to this standard maximum length of cable for transmission at 12 M bits/ sec is 5 m. Polling method is used to notify the CPU when the USB device is ready for data transmission.
USB 2.0 was launched in April 2000 which promises to deliver data transmission speed of 480 M bits/sec but on the ground it delivers speed of 35 M bits/sec to 280 M bits/sec. The USB supports 127 devices connected directly or through the USB hubs. USB devices supports hot plugging means when you plug or unplug them it is automatically detected by the computer. The Latency in USB 2.0 compatible devices for transmission of 1 bit is 125 microseconds. Twisted pair of cables is used to reduce noise and crosstalk. Incase of USB 2.0 standard maximum 3 m long cable can be used for transmitting data at 480 M bits/sec. Polling is used to notify CPU when the USB device is ready for data transmission.
USB 3.0 is the latest version recently launched in the market and is expected to deliver the 4.8 G bits/sec, which is 10 times greater as compared to the USB 2.0. It has eliminated the problem of excessive power consumption and latency. The bandwidth for data transmission is increased and it support full duplex communication means one route for transmitting data and another for receiving at the same time. It also provides more security as compared to the previous version and data is transferred in blocks of one byte which is scrambled, then it is transmitted in 10 bit format. This version is also compatible with the devices working on the older USB 2.0 version. With this speed now you can write 64 GB data within 20 minutes. The USB 3.0 consists of twice many cables to support super speed data transmission. It is expected to deliver 3.2 to 4 G bits/sec. In case of USB 3.0 a special signal is used to indicate whether the device is ready or not for data transmission.
If you are planning to buy new peripherals for your computer setup then you should go for USB 3.0 standard compatilble devices. You can also take advices for some of the well renowned companies like Impcsupport. They provide 24*7 online technical supports for all Windows OS compatible computer setup. They also provide reliable software solution for solving this purpose. By using the computer maintenance tools provided by them you can enhance the performance and speed of the computer.

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Bella Martin received the Master degree in software engineering in 2006 and currently serving as a software engineer at www.impcsupport.com/. She provides informative articles on Online PC Support, PC technical support, windows support, computer maintenance tools and software’s.

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