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USB Cheat Sheet (2022) (fabiensanglard.net)

514 points by gwerbret · 127 days ago · 87 comments on HN

Article summary

The article provides a cheat sheet for understanding USB terminology, including the differences between various USB generations and types, such as USB 2.0, 3.0, 3.1, and 3.2, as well as the features and capabilities of each. The cheat sheet also covers the physical characteristics of USB connectors, including the number of wires and lanes. The article aims to clarify the often-confusing world of USB standards and terminology. The author created the cheat sheet after spending time investigating a non-existent bug due to a misunderstanding of USB terms.

Main themes

  • USB terminology
  • USB generations and types
  • USB connectors and physical characteristics
  • Thunderbolt and USB4
  • Backwards compatibility
  • Naming conventions

What commenters say

  • The USB naming convention is misleading and confusing, making it difficult for consumers to understand the differences between various USB generations and types.
  • Thunderbolt 5 and USB4v2 are essentially the same thing in terms of protocol and bandwidth, but Thunderbolt 5 has additional requirements and guarantees.
  • The higher transfer speeds of newer USB versions, such as 20Gbps, are necessary for applications like video production, external SSDs, and eGPUs.
  • The USB-IF's naming convention is intentionally misleading to allow vendors to sell older generations of accessories as current, and USB 4 is not an improvement in this regard.
  • The distinction between USB 3.0, 3.1, and 3.2 is not clear, and the naming convention does not accurately reflect the actual speeds and capabilities of the devices.
  • Backwards compatibility is not always guaranteed with newer USB versions, and some devices may not function when connected to older ports.
  • The use of clear and concise labeling on USB hubs and devices, such as indicating the speed and capabilities of each port, is important for avoiding confusion and ensuring compatibility.
  • The relationship between Thunderbolt and USB4 is complex, with some arguing that USB4 is a superset of Thunderbolt 3, while others claim that Thunderbolt 4 is a strict profile of USB4 with additional requirements.