I need to connect my MacBook to a USB-C dock but the included USB-C cable isn't long enough. I have a several longer Thunderbolt 3 cables, so I wanted to know if I could connect the USB-C dock via a Thunderbolt 3 cable?

I realize I cannot do it the other way around, but I have never seen anywhere where it said you cannot do it the way I am proposing.

I'm using the CalDigit USB-C Dock.


Since Thunderbolt 3 is a "multi-plexing" of several signals including USB 3.1, you can use a Thunderbolt 3 cable in place of a USB-C cable. As you stated, it can't be done the other way around.


Well, as it turns out, while the TB3 cable will send some signals to the USB-C dock, it won't send a video signal on my CalDigit USB-C Dock. From what I can tell is all USB ports work, charging working, but it appears nothing else works.

  • Couple of things - 1) this is not what you originally asked; you asked about USBC, with no mention of video. 2) a TB cable must send video otherwise you wouldn't be able to daisy chain displays. Is your dock dropping the signal?
    – Allan
    Nov 24 '17 at 22:00
  • Sorry for the confusion, Allan. I said it was a USB-C dock, which in all known cases, includes video. Regardless, any and all TB3 cables I tried won't send a video signal from the Mac to the USB-C dock. Also, when I connect the USB-C cable, the Mac makes makes a chime sound. Connecting the TB3 cable, no sound is made. Nov 27 '17 at 1:53

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