USB Speeds

My previous post regarding USB drives (read here Should you pull out your USB or eject?) was one of the mostly viewed articles in the recent time. I thought to write about USB again,  and this time about the speed and the technology behind it. I assume this will help everyone  understand and benefit in their day to day life.

Universal Serial Bus (USB) is the communication protocol used between computers and electronic devices to communicate with each other. The initial usage of USB, did not support high speed data transmission but was intended to use with slower devices like mouse, keyboard, game consoles, etc. The evolution of USB devices can be noticed in parallel to its demand by various devices evolved in the market. Nowadays devices like tablets, smart-phones, game consoles, camera, scanner, etc and many more devices are connected through USB, allowing communication and recharging more convenient and faster.


The evolution of USB technology with time and speed.

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Evolution in detail – facts and figures

USB 1.0

  • Speed – 1.5 Mbps (Megabits per second) as a low speed device and 12 Mbps (Megabits per second) as a full speed device.

USB 2.0

  • High Speed (HS) – 480 Mbps (Megabits per second)
  • Half duplex – can either send or receive data
  • Power usage -Up to 500 mA

USB 3.0

  • Super Speed (SS) – 4.8 Gbps (Gigabits per second)
  • Full duplex – can send/ receive data asynchronously
  • Power usage -Up to 900 mA, more power efficient (less power in idle state)
  • Can power more devices
  • Backward compatible – can be used with USB 2.0 devices at the speed of USB 2.0.

USB 3.1

  • Super Speed (SS) – 10 Gbps (Gigabits per second)
  • Can power any type of device
  • C-type connector that plugs in without regarding to orientation.
  • Improved bus utilization using NRDY & ERDY packets to let a device asynchronously notify the host, of its readiness to function.

Hope you have an idea about USB, the speed and technology you need to choose next time. If you have any comments please post it below. If you have any queries, refer to this forum.

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