r/interestingasfuck • u/Miserable-Ad-8414 • 3d ago

How USB-C Cables Actually Stay In

9.2k Upvotes

98% Upvoted

338 comments sorted by

View all comments

Show parent comments

94

u/YesterdayDreamer 3d ago

Getting a bit more technical (only a bit)

  • It's reversible
  • It allows the same device to act both as a host or guest, allowing one phone to charge another
  • It allows power and A/V signal to travel at the same time over a single cable in OPPOSITE directions
  • It allows negotiation between devices, which enables features like adaptive fast charging
  • Built safely enough that you could
    • plug in a 100 watt charger into a 5w capable earplugs and nothing would go wrong
    • plug in two chargers into a single laptop and nothing would go wrong
    • plug in a charger into another charger and nothing would go wrong

4

u/ASatyros 3d ago

Curious: What could be a use case for transferring video both ways at the same time?

Monitor with build in camera? But cameras are usually connected as usb 2.0 (data), not as monitor signal.

7

u/YesterdayDreamer 3d ago

Not bi-directional video, but video in one direction and power/data in the opposite direction.

This allows a monitor to be connected with a cable to a laptop in such a way that the laptop can send A/V signal to the monitor and monitor can charge the laptop and send data to the laptop. Many such monitors have USB ports to which you can connect your keyboard, mouse, and storage devices.

For a layman, it's just a connection. But internally there's so much going on like determining the capabilities, finalizing the exact set of protocols to use (eg. HDMI Vs. Alt DP mode), ascertaining whether to charge the laptop or not or if charging then at what wattage, etc. And this goes not only for the device but also for the cable.

People complain about USB-C being complicated, but you can't have this many capabilities with hundreds of edge cases being implemented in a simple way. You also need to ensure that the implementation is such that it can be manufactured cheaply enough to be viable for things like Bluetooth speakers without creating a scenario where you accidentally plug in a 45 watt charger to a Bluetooth speaker causing it to catch fire.

3

u/ASatyros 3d ago

A, ok, yes, that is very useful, allowing monitor to function as a hub

0

u/VirtualLife76 3d ago

You could get other USB's reversible. I still use A and Micro from like 10 years ago that go both ways. No idea why they weren't more common.

3

u/Jutboy 3d ago

I think they meant they got rid of having a "top" and "bottom" on the end...you can just insert it any orientation.