Differentiate between a PS/2 and USB connector for keyboards and mice.

PS/2 and USB are two different types of connectors used for connecting keyboards and mice to computers. Let's delve into the technical details of each:

PS/2 Connector:

  1. Physical Characteristics:
    • The PS/2 connector has a round shape with six pins.
    • It is color-coded, with purple for keyboards and green for mice.
  2. Data Transfer Protocol:
    • PS/2 uses a synchronous serial communication protocol.
    • It employs a bidirectional communication, allowing data to be sent from the device to the computer and vice versa.
  3. Power Consumption:
    • PS/2 devices are powered by the computer's power supply.
    • The keyboard and mouse each require a small amount of power.
  4. Hot Swapping:
    • PS/2 does not support hot-swapping, meaning you should typically connect or disconnect devices when the computer is powered off.
  5. Polling Rate:
    • PS/2 devices have a lower maximum polling rate compared to USB.
    • The standard polling rate is around 60-100 Hz.
  6. Daisy Chaining:
    • It's possible to daisy chain multiple PS/2 devices using a splitter, although this is less common.

USB Connector:

  1. Physical Characteristics:
    • USB connectors are flat and rectangular in shape with four pins.
    • USB connectors are standard across devices, so there's no color-coding specifically for keyboards or mice.
  2. Data Transfer Protocol:
    • USB uses a serial communication protocol with a host-controller architecture.
    • It supports bidirectional communication, similar to PS/2.
  3. Power Consumption:
    • USB devices are self-powered and draw power from the computer's USB port.
    • This allows USB devices to have more advanced features without relying on the computer's power supply.
  4. Hot Swapping:
    • USB supports hot-swapping, meaning you can connect or disconnect devices while the computer is powered on.
  5. Polling Rate:
    • USB devices typically have a higher maximum polling rate compared to PS/2.
    • Common polling rates are 125 Hz, 250 Hz, 500 Hz, and 1000 Hz.
  6. Daisy Chaining:
    • USB supports daisy chaining through hubs, making it easier to connect multiple devices to a single USB port.


  • PS/2:
    • Older technology, but still used in some applications.
    • Typically found on legacy systems or specialized equipment.
    • Lower polling rate and lacks hot-swapping support.
  • USB:
    • Widely adopted and versatile.
    • Supports higher polling rates, hot-swapping, and can provide power to devices.
    • Standard for modern computers and peripherals.