Lecture Notes: USB and Thunderbolt Connections

Overview of USB (Universal Serial Bus)

• Purpose: Connect peripherals (mouse, keyboard, printer) to computers.
• Early Version: USB 1.1
  • Low Speed: 1.5 Mbps, max cable length of 3 meters.
  • Full Speed: 12 Mbps, max cable length of 5 meters.

USB Evolution

USB 2.0

• Speed: Increased to 480 Mbps.
• Max Cable Length: 5 meters.

USB 3.0

• Also Known As: SuperSpeed USB.
• Speed: 5 Gbps.
• Common Cable Length: 3 meters.
• Connectors:
  • Standard A plug (similar to prior versions).
  • Newer versions of B, Mini B, Micro B plugs for higher speeds.

USB-C

• Features:
  • Reversible connector, no orientation issues.
  • Supports data, video, and other signals.
  • Slightly larger than Micro B, symmetric.

USB Naming and Standards

• USB 3.0: Referred to as USB 3.1 Gen 1 (SuperSpeed, 5 Gbps).
• USB 3.1 Gen 2: Known as SuperSpeed Plus, 10 Gbps.
• USB 3.2:
  • Uses USB-C connectors.
  • New standards:
    • USB 3.2 Gen 1 (formerly USB 3.0/USB 3.1 Gen 1): 5 Gbps.
    • USB 3.2 Gen 2 (formerly USB 3.1 Gen 2): 10 Gbps.
    • USB 3.2 Gen 1x2: 10 Gbps using two Gen 1 lanes.
    • USB 3.2 Gen 2x2: 20 Gbps using two Gen 2 lanes.

Thunderbolt Connections

• General Info: High-speed serial connection for data and power.
• Physical Connectors: Initially used Mini DisplayPort, now uses USB-C.

Thunderbolt Versions

• Thunderbolt 1:
  • 2 channels, 10 Gbps each, total 20 Gbps.
• Thunderbolt 2:
  • Aggregated channels, 20 Gbps.
• Thunderbolt 3:
  • USB-C connector.
  • Total throughput: 40 Gbps.
  • Supports copper (3 meters) and fiber (60 meters).
  • Allows daisy chaining up to 6 devices.

Legacy Connections

• Serial Connections: Used before USB.
• Standards: 9-pin and 25-pin serial connections.
• Technology: RS-232 signals for serial communication.
• Current Use: Still found in DB9/DB25 connectors for serial consoles (switches, routers, firewalls).