Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!polyslo!jdudeck
From: jdudeck@polyslo.CalPoly.EDU (John R. Dudeck)
Newsgroups: comp.sys.ibm.pc
Subject: Re: TTL Mono Monitor and Composite Mono Monitors
Keywords: TTL COMPOSITE MONOCHROME MONITORS
Message-ID: <25be3db6.6fb3@polyslo.CalPoly.EDU>
Date: 24 Jan 90 23:43:50 GMT
References: <13120.25bb055b@max.u.washington.edu> <7601@cbnewsh.ATT.COM>
Reply-To: jdudeck@polyslo.CalPoly.EDU (John R. Dudeck)
Organization: Cal Poly State University -- San Luis Obispo
Lines: 18


>| If the difference goes beyond difference in connector-type, how
>| difficult is it to adopt a TTL monochrome monitor so that it will  
>| accept the signals that a Composite monochrome monitor would accept.
>
Why do you want to do this?  Is it for a computer such as an old home-
style TI 99/4A or Atari?  If we are talking about systems previous to the
VGA which is analog, most video cards have TTL outputs in addition to 
any composite video output that they may have.

The problem comes with systems that have the older CGA type of RGB output,
which many monochrome TTL monitors can't take.  The R, G, and B outputs
are on different pins of the connector from the monochrome video signal
that the monitor expects.  Some monochrome monitors will accept RGB and
convert it to different shades of monochrome.  For example, the Princeton
MAX-12 does this, as does the Thomson 450A.  If you have an EGA card,
there should be an EGA monochrome output that is compatible with standard
mono monitors.

-- 
John Dudeck                           "You want to read the code closely..." 
jdudeck@Polyslo.CalPoly.Edu             -- C. Staley, in OS course, teaching 
ESL: 62013975 Tel: 805-545-9549          Tanenbaum's MINIX operating system.