cvt is now bundled in xorg.

the history of CVT:

  DDC 1994

  DMT = Discrete Monitor Timings
     started in 1989

     DMT Version 1.0, Revision 0.8 (1998)
         = 28 VESA Standards 
	 + 3 VESA Guidelines (approved, but not endorsed by VESA) 
	 + 2 Industry Standards.

  GTF in 1996
      designed for CRT
      doesn't account for different aspect ratios

  CVT in 2003
      to replace GTF

  CVT-RB = Coordinated Video Timings-Reduced Blanking 

http://www.dell.com/downloads/global/vectors/2003_cvt.pdf
http://www.vesa.org/Public/EEDIDguideV1.pdf