TELNET ANSI COLOR SUPPORT


TELNET supports ANSI color mode in addition to video attribute color
mapping. Video attribute color mapping is mapping of colors to normal VT320
monochrome attributes such as bold, reverse video, and underline. Video
attribute mapping is configured through the Screen Setup Menu.

ANSI color support allows the character, character cell, and screen
background colors to be selected directly by sending control sequences from
the host.

ANSI colors are selected through extensions to the VT320 Set Character
Attributes control sequence. The following table describes the control
sequences supported.


  <CSI> Ps;Ps...m     Set Character Attributes and ANSI Colors

                      Character Attributes
       Ps = 0         Resets all colors and video attributes to defaults

       Ps = 1         Bold on. If the text color has been changed using an
                      ANSI color control sequence, bold will be the
                      intensified text color. Otherwise bolded text will
                      display as configured in the Screen Setup Menu.

       Ps = 4         Underscore on. Always uses the colors selected in
                      the Screen Setup Menu.

       Ps = 5         Blink on

       Ps = 7         Reverse video on. Always uses the colors selected in
                      the Screen Setup Menu.

       Ps = 22        Bold off, normal intensity

       Ps = 24        Underscore off

       Ps = 25        Blink off

       Ps = 27        Reverse video off, positive image

                      Character Colors (low intensity unless bolded)
       Ps = 30        Black
       Ps = 31        Red
       Ps = 32        Green
       Ps = 33        Yellow (displays as brown unless bolded)   
       Ps = 34        Blue
       Ps = 35        Magenta 
       Ps = 36        Cyan
       Ps = 37        White
       Ps = 39        White
 <CSI> Ps;Ps;...m    Set Character Attributes and ANSI Colors

                      Character Cell Color (always low intensity colors)
       Ps = 40        Sets the cell color to the current  background color
       Ps = 41        Red
       Ps = 42        Green
       Ps = 43        Yellow (displays as brown)
       Ps = 44        Blue
       Ps = 45        Magenta
       Ps = 46        Cyan
       Ps = 47        White
       Ps = 49        Sets the cell color to the current background color

                      Direct Index Control Using a Prefix
       < index        Specifies the character color index
       = index        Specifies the character cell color index
       > index        Specifies the screen background index
          ANSI Color Indexes  
          0 = black
          1 = red
          2 = green
          3 = yellow
          4 = blue
          5 = magenta
          6 = cyan
          7 = white

The following examples use the emulator command DISPLAY to locally test the
character attributes and colors.

Example 1:  CMD> DISPLAY "<CSI>1;35mBold magenta characters<CSI>0m"
                      or
            CMD> DISPLAY "<CSI>1;<5mBold magenta characters<CSI>0m"

            Displays the character string in bold magenta characters at
            the current cursor position.


Example 2:  CMD> DISPLAY "<CSI>5;7mReverse blinking characters<CSI>25m"

            Displays the character string using the blink attribute, 5,
            and the reverse video attribute, 7. After the characters are
            displayed, the blink is turned off, 25. Subsequent characters
            display in reverse video.

Example 3:  CMD> DISPLAY "<CSI>1;33;43mYellow chars in brown cell<CSI>0m"

            Displays the character string using the bold attribute and
            character color 33 to give yellow characters. The character
            cell color, 43, shows as brown directly around each character.