3 ms·
USB-C cables either have all 4 superspeed lanes wired up, or none of them. Which is why USB-C docks with video worked (2 lanes for USB, 2 lanes for DisplayPort)
by brigade 6y ago
USB-C cables either have all 4 superspeed lanes wired up, or none of them. Which is why USB-C docks with video worked (2 lanes for USB, 2 lanes for DisplayPort) and why 2x2 isn't supposed to require new cables.
Thunderbolt still works at 20gbps over "normal" superspeed USB-C cables; the markup you're paying is generally for cables rated for 40gbps.
- eqvinox 6y agoYour first paragraph is technically right but in actual reality cables with only 2 superspeed lanes exist. Also, the article (and comment) aren't solely about Type C; USB3 cables going to good ol' A/B will only have 2 superspeed lanes. Your second paragraph is half-wrong. Thunderbolt cables must have an e-marker: refer to https://www.usb.org/sites/default/files/USB%20Type-C%20Spec%20R2.0%20-%20August%202019.pdf https://www.usb.org/sites/default/files/USB%20Type-C%20Spec%... Figure F-1 ("SOP'"). If the cable has an e-marker but doesn't have the Thunderbolt ID, you get passive Gen2. However, the problem is that USB3 TypeC-C cables aren't required to have an e-marker at all... in which case you drop out at the very first fork in the flow diagram. This also leads to the funny situation that any 5A USB3 cable should work for Thunderbolt (because 5A requires the e-marker), while 3A cables may or may not work. I mean, of course the power rating makes complete sense to determine TB3 capability, right? :D