USB Technology Overview

Jul 6, 2025

Overview

This lecture explains the purpose, evolution, versions, cable types, connectors, and port color coding of USB (Universal Serial Bus) technology.

Introduction to USB

  • USB stands for Universal Serial Bus and is the standard for connecting peripherals to computers.
  • USB supports devices such as keyboards, mice, cameras, printers, scanners, drives, and even charging devices.
  • Key goals include universal connectivity, easy configuration, and fast data transfer.
  • USB ports are hot-swappable, allowing devices to connect/disconnect without powering off.
  • USB can provide power to small devices without extra power cables.

Evolution and Versions of USB

  • USB 1.0 (1996): 1.5 Mbps transfer speed.
  • USB 1.1 (1998): 12 Mbps.
  • USB 2.0 (2000, "High Speed"): 480 Mbps.
  • USB 3.0 (2008, "SuperSpeed"): 5 Gbps.
  • USB 3.1 (2013, "SuperSpeed Plus"): 10 Gbps.
  • USB 3.2: 20 Gbps.
  • USB 4 (2019): 40 Gbps.

USB Cables and Connectors

  • USB cables usually have two connector types: Type A, Type B, or Type C.
  • Type A: Standard rectangular plug, common as the host connector on computers.
  • Type B: Squarish plug for devices like printers and some drives.
  • Mini-B: Smaller than B, used on older smartphones and cameras.
  • Micro-B: Thinner than mini-B, used on modern smartphones and devices.
  • USB 3.0 Type B: Larger with nine pins, for higher speeds and power.
  • USB 3.0 Micro-B: Wider version with extra pins for external hard drives.
  • Type C: Thin, rounded, 24 pins, reversible, used on modern devices; same connector at both cable ends.

USB Port Color Coding

  • USB 1.0/1.1: White port (outdated, rare on new hardware).
  • USB 2.0: Black port.
  • USB 3.0: Blue port.
  • USB 3.1: Teal port.
  • USB 3.2: Red port.
  • Sleep and Charge ports: Red, orange, or yellow (provide power during sleep mode).

Key Terms & Definitions

  • USB (Universal Serial Bus) — Standard for connecting peripherals to computers.
  • Hot-swappable — Devices can be connected/disconnected without shutting down.
  • Type A Connector — Standard rectangular USB plug for hosts.
  • Type B Connector — Square USB plug for devices.
  • Mini-B/Micro-B Connector — Smaller USB connectors for compact devices.
  • Type C Connector — Reversible, universal USB connector used in modern devices.
  • Sleep and Charge Port — USB port that continues to supply power when the computer sleeps.

Action Items / Next Steps

  • Review USB versions, connector types, and port color codes for upcoming quiz.