Universal Serial Bus (USB) (Cambridge (CIE) O Level Computer Science)

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The Universal Serial Bus (USB) is an asynchronous and serial method of transmitting data between devices and has become an industry standard
Many devices use USB such as keyboards, mice, video cameras, printers, portable media players, mobile phones, disk drives, network adapters, etc
Different USB connectors exist for different devices:
- USB-A (flash drives, mice, keyboards, external HDD, etc)
- USB-B (printers, scanners, optical drives, floppy drives, etc)
- USB-C (new standard of USB due to its small size and speed)
When a device is connected to a USB port the computer:
- Automatically detects that the device has been connected
- Automatically recognises and the appropriate device driver is loaded so that the device can communicate with the computer
- If the device is new, the computer will look for a matching device driver
- If one cannot be found then the user must download and install an appropriate driver manually

Advantages	Disadvantages
Devices are automatically detected and drivers are automatically loaded for communication	The maximum cable length is roughly 5 metres meaning it cannot be used over long distances, limiting its use
Cable connectors fit in only one way. This prevents incorrect connections and ensures compatible data transmission	Older versions of USB have limited transmission rates for example USB 2.0 has 480Mbps
As USB usage is standardised, there is a lot of support available online and from retailers	Very old USB standards may not be supported in the near future (USB 1.1, USB 2.0, etc)
Several different data transmission rates are supported. The newest transmission rate as of 2022 is USB4 2.0 with 80 Gbps (81,920 Mbps, 170x faster than USB 2.0)
Newer USB standards are backwards compatible with older USB standards

Julia uses a USB connection to transfer data onto her USB flash memory drive.

One benefit of using a USB connection is that it is a universal connection.

(i) State two other benefits of using a USB connection.

[2]

(ii) Identify the type of data transmission used in a USB connection.

[1]

Answers

(i) Any two of:

(ii)

to absolutely everything:

the (exam) results speak for themselves:

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