3 ms·

That's not true for PD charging cables though right? They are generally USB2 speeds if they have data pins beyond what's required for PD charging at all but the

by rtkwe 3y ago

That's not true for PD charging cables though right? They are generally USB2 speeds if they have data pins beyond what's required for PD charging at all but they're just direct electrical cables without any chips as far as I know. https://www.lumafield.com/article/usb-c-cable-charger-head-to-head-comparison-apple-thunderbolt-amazon-basics https://www.lumafield.com/article/usb-c-cable-charger-head-t...

lazide 3y ago
Devices could (and usability wise I wish they would!) show low data speed only warnings. No OS’s I know of currently do. The device definitely knows, all the information is accessible in the USB info if you know the special tools to run to dump it.
- lxgr 3y ago
  At least Windows used to do this for USB 3 (before USB-C was a thing) devices plugged into an USB 2 port when the computer also had USB 3 ports available: https://superuser.com/questions/1022542/windows-10-display-a-warning-if-i-plug-a-usb-3-0-device-into-a-usb-2-0-port https://superuser.com/questions/1022542/windows-10-display-a... It would seem that with e-markers in USB-C cable (and assuming that USB 3/4 still expose device information like that to the host), an extended version of this should be possible: "Your computer and this device support x Gbps, but your cable caps out at y Gbps; use a better cable to make this connection faster".
  - lazide 3y ago
    They can do the opposite direction too, detecting a USB2.0 cable when a higher speed one is needed. It still boggles my mind that no corresponding warning pops up. Even without an e-marker, there has to be some way to know that the client device can support a higher speed and warn the user - it seems like USB device capabilities supports that? [https://developer.apple.com/documentation/iokit/1425036-usb_device_capability_type_const https://developer.apple.com/documentation/iokit/1425036-usb_...]
lxgr 3y ago
Per the specifications, the absence of an actual chip serves as a one-bit marker indicating "this cable supports 3A and USB 2 speeds" :) 5A already needs a marker, even at USB 2 speeds!

by rtkwe 3y ago

lazide 3y ago

Devices could (and usability wise I wish they would!) show low data speed only warnings. No OS’s I know of currently do. The device definitely knows, all the information is accessible in the USB info if you know the special tools to run to dump it.

lxgr 3y ago
At least Windows used to do this for USB 3 (before USB-C was a thing) devices plugged into an USB 2 port when the computer also had USB 3 ports available: https://superuser.com/questions/1022542/windows-10-display-a-warning-if-i-plug-a-usb-3-0-device-into-a-usb-2-0-port https://superuser.com/questions/1022542/windows-10-display-a... It would seem that with e-markers in USB-C cable (and assuming that USB 3/4 still expose device information like that to the host), an extended version of this should be possible: "Your computer and this device support x Gbps, but your cable caps out at y Gbps; use a better cable to make this connection faster".
- lazide 3y ago
  They can do the opposite direction too, detecting a USB2.0 cable when a higher speed one is needed. It still boggles my mind that no corresponding warning pops up. Even without an e-marker, there has to be some way to know that the client device can support a higher speed and warn the user - it seems like USB device capabilities supports that? [https://developer.apple.com/documentation/iokit/1425036-usb_device_capability_type_const https://developer.apple.com/documentation/iokit/1425036-usb_...]

lxgr 3y ago

Per the specifications, the absence of an actual chip serves as a one-bit marker indicating "this cable supports 3A and USB 2 speeds" :) 5A already needs a marker, even at USB 2 speeds!