USB Cheat Sheet

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TLDR

  • A reference sheet mapping USB generations, speeds, connector types, and naming conventions across the full USB standard history.

Key Takeaways

  • USB 3.2 Gen naming uses generation for speed tier and “by” for lane width, roughly paralleling PCIe naming conventions.
  • USB 3, USB 3.1, and USB 3.2 refer to overlapping spec revisions, making chipset speed claims (5-20 Gbps) ambiguous without Gen/lane qualifiers.
  • USB4v2 introduces PAM3 11b/7t line encoding, a significant shift from earlier USB signaling schemes.
  • Power Delivery generations and profiles are part of the USB ecosystem but often omitted from quick-reference materials.

Hacker News Comment Review

  • The 3.2 Gen x By x naming draws split reactions: technically defensible (parallels PCIe), but vendor abuse means “supports 3.1 or 3.2” still leaves a 5-20 Gbps ambiguity in practice.
  • Commenters flag gaps: no female/male Type-C pinouts, no PD profile breakdown, no PAM3 signaling detail for USB4v2, and no placement of Thunderbolt 5 in the hierarchy.

Notable Comments

  • @15155: Flags missing PAM3 11b/7t encoding detail for USB4v2 and calls for PD generations/profiles coverage.
  • @brcmthrowaway: Raises where Thunderbolt 5 fits into the sheet’s taxonomy.

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