USB
- 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. Some examples are:
- USB-A (flash drives, mice, keyboards, external HDD, etc)
- USB-B (printers, scanners, optical drives, floppy drives, etc)
- USB-C
- USB-C is becoming the new standard of USB due to its small size and speed
- When a device is connected to a USB port the computer is:
- Automatically detects that the device has been connected
- Automatically recognised 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 and disadvantages of USB
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Devices are automatically detected and drivers are automatically loaded for communication. This simplifies the data transmission process for the user |
The maximum cable length is roughly 5 metres meaning it cannot be used over long distances, limiting its use |
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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 |
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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) |
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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) |
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Newer USB standards are backwards compatible with older USB standards |
Worked example
Julia uses a USB connection to transfer data onto her USB flash memory drive.
(i) One benefit of using a USB connection is that it is a universal connection. State two other benefits of using a USB connection.
[2]
- Any two of:
- It cannot be inserted incorrectly [1]
- Supports different transmission speeds [1]
- High speed transmission [1]
- Automatically detected [1]
- Powers the device for data transfer [1]
(ii) Identify the type of data transmission used in a USB connection.
[1]
- Serial [1]
