Displayport Alt Mode

Explainer details why USB-C to HDMI adapters often fail to deliver full video quality

A technology explainer outlines how USB-C to HDMI adapters work, noting that video output depends on a USB-C port supporting DisplayPort Alternate Mode or Thunderbolt, a fully-featured cable capable of carrying video signals, and an adapter with a chip to convert the signal into HDMI. It notes that DisplayPort 1.4 supports up to 8K at 60Hz while DisplayPort 1.2 tops out at 4K at 60Hz, and that basic charging cables cannot transmit video at all.

engadget.com · 2026-10-05

Why some monitors need a separate USB cable for their hub ports to work

Monitors with built-in USB hubs use two types of ports: an upstream port that links the monitor to a computer, and downstream ports where peripherals like keyboards or drives connect. If a monitor's video signal runs over HDMI or DisplayPort, those cables don't carry USB data, so a separate USB upstream cable is required for the hub's downstream ports to function. USB-C can eliminate that extra cable when the monitor and cable support DisplayPort Alt Mode and USB Power Delivery.

engadget.com · 2026-09-19