A community member on Hacker News posted a compact reference sheet for USB standards after confusing terminology led to a wild goose chase. The cheat sheet lines up marketing names, signal rates, and typical cable lengths from the original USB 1.1 up through USB 4.0. It shows USB 3.2 Gen 2×2 reaching 20 Gbps over roughly 80 mm, while USB 4 Gen 3×2 pushes 40 Gbps across a 120‑mm lead.

The table also clarifies lane usage: a four‑wire pair supports a single half‑duplex lane, eight wires give two full‑duplex lanes, and twelve wires—found only on Type‑C connectors—enable four lanes. Encoding schemes such as 8b/10b shave about 20 % off the raw rate, so USB 4 Gen 2×2, rated at 20 Gbps, delivers roughly 2 500 MiB/s in practice. Sequential reads fall short of the theoretical maximum, hovering around 1 200 MiB/s for USB 3.2 Gen 2.

Power delivery ranges from the legacy 5 V 500 mA USB 2.0 line to the latest USB‑PD 3.1 EPR profile that pushes 48 V 5 A for 240 W of output. The sheet lists connector families—Type‑A and Type‑B with four or eight wires, and the 24‑pin Type‑C with twelve wires—matching lane count and power budget. Using the correct combination avoids costly mis‑wiring and speeds up hardware debugging.