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Re: Advice on laptop with USB-C port and USB-Type C Multipoint Adapter (and VGA)

On Thu, Dec 03, 2020 at 08:35:37PM +1100, David wrote:
> On Thu, 3 Dec 2020 at 02:27, <rhkramer@gmail.com> wrote:
> > I did find out that a USB-C cable / connector has 24 conductors -- so it is
> > conceivable (with my lack of knowledge) that some laptop manufacturers
> > actually put out an (analog) VGA signal on the USB-C cable.
> Is this just wishful thinking or do you have evidence?
> Because it's inconceivable, as far as I'm aware. Everything I have read
> about USB-C indicates that it is purely digital. Even though it seems
> to be the USB way to have countless variations of every physical and
> electrical specification, VGA is a standard from 1987, forget finding
> it on any USB-C connector. Those pins are all used for other things.

USB-C is a mess. Quoth [1]:

   "A device with a Type-C connector does not necessarily
   implement USB, USB Power Delivery, or any Alternate Mode:
   the Type-C connector is common to several technologies while
   mandating only a few of them"

That said, Display Port, Thunderbolt, MHL and HDMI alternate modes seem
to implement VGA output with an "active" cable, which is an euphemism
for "there's some chips in there".

So your computer's USB-C socket must fit, your dongle, aka "active
cable" must fit, and they have to be capable to talk to each other.

 - t

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