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

On Jo, 03 dec 20, 08:49:58, rhkramer@gmail.com wrote:
> On Thursday, December 03, 2020 04:35:37 AM 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?
> Well, I guess it could be called wishful thinking, but I tried to be pretty 
> clear where I was coming from: "it is conceivable (with my lack of knowledge) 
> that some laptop manufacturers actually put out an (analog) VGA signal on the 
> USB-C cable.
> But I don't know what those 24 conductors are for, and I thought it was 
> possible some were reserved for future use (or with the alternate modes) -- I 
> guess your answer clarifies that there aren't any such "spare" conductors.
I know from experience what a difference it makes to use a better 
(typically thicker) VGA cable, especially over longer distances.

Even the high quality USB-C cables with support for power delivery are 
thinner than a VGA cable. There's no "room" for analog signals there.  
Similar for the connector.
> > 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.

Display devices manufactured in the last (10? 20?) years are using 
digital technology (LCD, OLED, etc.) and have a digital input port (DVI, 
HDMI or DisplayPort[1]).

Conversion to (video card to VGA output) and from analog (VGA input to 
digital display) is wasting money for the DAC/ADC and signal quality[2].

It wouldn't make sense to "hold back" a new connector like Type C with 
support for analog signals (besides the size requirements). These USB to 
VGA adapters are meant for older devices without a digital input that 
are still worth keeping around (e.g. projectors).

[1] DVI, HDMI and DisplayPort are signal compatible, conversion is done 
with passive adaptors or cables.
[2] do yourself a favour and use a digital connection between computer 
and display device whenever possible.

Kind regards,

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