The USB-C Cheat Sheet

So you’ve got a USB-C device, maybe a Pixel phone or a MacBook Pro, you’re now in the wonderful world of universal connectivity, right?

Disclaimer: I’m aggregating this information for my own benefit and thought it would be useful for others. Use at your own risk.

USB Type-C is a great concept, but there are a few caveats:

What can the USB-C plug specification carry?

1. Thunderbolt 3 (which is a superset of the specs below)
2. USB 2.0
3. USB 3.0 (5Gbps) — Also known as USB 3.1 Gen 1
4. USB 3.1 Gen 2 (10Gbps)
5. DisplayPort
6. PCIe 3rd Gen
7. HDMI 1.4b using Alt-Mode (no 2.0b yet)
8. USB Power Delivery (PD) — Charging Power up to 100W

It’s worth remembering that USB-C is NOT the same as USB 3.x. USB-C is only the plug/connector.

What cable do I need?

This is where it gets complicated. There are an almost infinite number of potential combinations of specs that can make up a USB-C cable. To help you compare, a few considerations follow.

Power delivery

USB-C can carry up to 100W of power using the “Power Delivery” spec. However not all the cables can carry that much and most cables on the market appear to be rated up to 60W. This is not enough to power something like a the 87W Apple MacBook Pro Late 2016, for that you’ll need a rarer 100W specification cable.

Check your device to see how many watts it can use.

Note that most charging cables that ship with laptops/phones (e.g. Late 2016 MacBook Pro) are actually USB 2.0 and not able to handle the higher speeds/capabilities of USB 3.x etc.

USB-C max cable lengths

USB-C cables are very sensitive to their length as the high throughput specs that are carried over it are susceptible to signal degredation (unless carried optically).

USB 2.0: 4m USB 3.1 Gen 1: 2mUSB 3.1 Gen 2: 1m Thunderbolt 3 — Passive cables at 40Gbps: 0.5mThunderbolt 3 — Passive cables at 20Gbps: 2mThunderbolt 3 — Active cables at 40Gbps: 2m — 60m (optical)

Supported protocols

Thunderbolt 3 is the killer spec that encompasses all the other specs. So if you want an all-purpose cable, you will probably want one of these. They are however much more expensive and you still need to be careful as to how much power they can carry.

I haven’t been able to find a definitive source for what cables will otherwise support which protocols other than them being labelled as USB2.0 USB-C, USB 3.0 USB-C etc.

Conclusion

Thunderbolt 3 cables will give you everything at a price, but if all you care about is charging, then a USB2.0 will do you fine and give you longer reach.

Update: My friend Tom just pointed out that you should also get certified cables as ones that don’t meet the spec can fry your hardware.

Update 2: My friend Essa gave me a handy link to this, which leads to a spreadsheet created by a Google engineer who has tested cables himself: https://www.reddit.com/r/Nexus6P/comments/3robzo/google_spreadsheet_for_usbc_cables_with_benson/

_References:_https://blog.startech.com/post/thunderbolt-3-the-basics/http://www.hdmi.org/manufacturer/HDMIAltModeUSBTypeC.aspxhttp://blog.fosketts.net/2016/10/29/total-nightmare-usb-c-thunderbolt-3/https://www.cnet.com/uk/how-to/usb-type-c-thunderbolt-3-one-cable-to-connect-them-all/