[Sussex] 2 monitors, one machine

[Mark Harrison (Groups)]

On Thu, 2005-10-06 at 17:33 +0100, Rob Malpass wrote:
> 
> Sorry for all these questions, it seems VGA is VGA, S-Video is also
> S-VHS 
> and unsuitable for monitors, but what is DVI, is this the new HDTV 
> connection?

Ah - as ever, it's slightly more complex than that :-)

S-Video refers to a connector type.

S-VHS refers to two things. 

- Firstly it is used to refer to a modification to the VHS tape
recording system to allow higher resolution (though still not as good as
DVD). 

- Secondly, it is often used colloquially to refer to the connector type
that such VHS recorders normally come with - S-Video.


VGA likewise refers to two different things.

- Firstly, it refers to the 15-pin analogue connector used for PC
monitors that we are all familiar with.

- Secondly, it refers specifically to a screen resolution of 640x480.
There was a period in which screen resolutions HIGHER than 640x480 used
to be referred to by numbers, now letters are commonly used:

--- VGA (640x480)
--- SVGA (800x600)
--- XGA (1024x768)
--- SXGA (1280x1024)
--- UXGA (1600x1200)
--- QXGA (2048x1536)

plus the "widescreen derivatives"

--- WVGA (854x480)
--- WSVGA (960x540)
--- WSGA (1024x576)
--- WXGA (1280x720) (this is the NATIVE resolution for the 720p HDTV
standard)
... and some others that are virtually never used at the moment, but
will come into their own over the next few years, I'm sure.


DVI is a purely digital connector. That is to say that the data
transfers as a digital stream into the monitor, where it is decoded and
rendered. DVI looks kind of odd - a lattice of pins, with a whole bunch
of different physical possibilities between 17 and 29 pins. 

It has at most a block of 24 small pins (carrying in round terms the
digital signals), 4 bigger ones (carrying analogue signals - ho hum),
and a long thin one (analogue ground), not all of which are used by any
given player.)

HDMI is the new "HDTV" connection. It supports video, sound and control
signals. It also allows bi-directional communication so an HDMI plasma
panel can communicate BACK to a DVD player what resolutions is support
natively, and allow the DVD player to choose which digital stream to
send! Funky, heh? It uses a 19-pin connector with "small pins" that sort
of looks like a USB cable-ish :-)

I hope this helps more than it confuses :-)

M.