25 - Peripheral Cables - 3.2

USB (Universal Serial Bus)

  • USB is the standard connection type for various peripheral devices (e.g., keyboards, mice).

USB Versions

  • USB 1.1:

    • Two speeds:

    • Low speed: 1.5 megabits per second.

    • Full speed: 12 megabits per second.

    • Cable lengths:

    • Low speed: typically 3 meters.

    • Full speed: typically 5 meters.

  • USB 2.0:

    • Maximum throughput: 480 megabits per second.

    • Standard cable length: approximately 5 meters.

  • USB 3.0 (SuperSpeed):

    • Maximum throughput: 5 gigabits per second.

    • Standard cable length: approximately 3 meters.

  • USB 3.1:

    • Maximum throughput: 10 gigabits per second.

  • USB 3.2:

    • Maximum throughput: 20 gigabits per second.

  • Note: USB specifications do not guarantee exact cable lengths, but the mentioned lengths are generally the maximum for maintaining throughput.

USB Connector Types

  • Common connectors:

    • Standard A Plug:

    • Widely used in peripheral connections.

    • Standard B Plug:

    • More square-shaped, often used for printers or external devices.

    • Mini B Plug and Micro B Plug:

    • Smaller connectors typically used for mobile devices.

  • USB 3.0 Connector Changes:

    • Standard A Plug retains the same form factor as previous versions.

    • Standard B Plug has been updated (taller).

    • Micro B Plug for USB 3.0 is a different form factor compared to USB 1.1 and 2.0's Micro B plug.

  • USB-C Connector:

    • A universal connector designed to replace multiple older USB connector types.

    • Can be connected in either orientation.

    • Describes the physical interface but not the signal type transmitted.

    • Size comparison: similar to Micro B but distinct from Standard A.

Legacy Serial Connections

  • Prior to USB, serial cables were common, with types such as:

    • DB-9 Connector: 9 pins, often referred to as DE-9.

    • DB-25 Connector: 25 pins.

  • RS-232 Standard:

    • Stands for Recommended Standard 232; used for sending serial data since 1969.

    • Legacy equipment often uses DB-9 or DB-25 connectors for devices like modems, keyboards, and mice.

  • Using DB-9 connectors today typically involves connecting to older network equipment (e.g., switches, routers) for configuration via console ports.

    • Console ports may also be RJ-45 connections for serial data rather than Ethernet.

    • Many modern computers do not have DB-9 connectors; converters to USB may be necessary.

Connecting with Thunderbolt

  • Thunderbolt: A high-speed serial connection capable of carrying both data and power in a single cable.

Thunderbolt Versions

  • Thunderbolt 1:

    • Used mini DisplayPort connector.

    • Throughput: two channels at 10 gigabits per second each (total 20 gigabits).

  • Thunderbolt 2:

    • Increased throughput to 20 gigabits aggregated.

  • Thunderbolt 3:

    • Uses USB-C connector.

    • Provides 40 gigabits of aggregate throughput.

    • Standard cable length: 3 meters for copper; up to 60 meters for optical.

    • Allows daisy chaining of devices.

  • Thunderbolt 4:

    • Maintains 40 gigabits of aggregate throughput.

    • Supports dual 4K video output.

    • Increases PCI Express bandwidth for better data transfer from the motherboard to peripheral devices.