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VT100 Codes

One of the ways one may place older computers onto the Internet is to dial into Unix shell accounts or gopher-based accounts. The Unix machine interacts with the Internet; the computer running the terminal emulator is only a simple input/output device. Many Freenet accounts work on the gopher-based shell principle.

The Digital VT100 terminal has become a standard that most Unix machines require. The mail readers, Usenet news readers, and Lynx text-only browsers often require strict adherence to VT100 compatibility. A subset or modified set of the VT100 codes are used for ANSI terminals. Often ANSI compatibility is not enough to interface with the most rigorous applications. Lynx is often cited as a benchmark. If your VT100 emulation works with Lynx, your emulation is pretty good.

The NEC PC-8201A TELCOM is not VT100 compatible. It understands some VT52 terminal sequences, but TELCOM is not up to the job of acting as a terminal for PINE, tin, and Lynx (three of the more popular Unix-based Internet tools). Ever since I got a NEC PC-8201A, I've wanted a VT100 terminal emulator for it. I have not found or programmed one - yet. Here is a list of the VT100 codes found on the net by Roger Merchberger, host of the current Tandy Model 100 Listserv.

                                Villanova University
                        Campus Computing - Terminal Emulation
                  Includes VT100 and VT52 Terminal and Control Codes

        This file contains control and terminal codes for the VT100 terminals,
ANSI terminals, and VT52 terminals. Many of the codes were derived from PC/
Intercomm, from Mark of the Unicorn Software.  I have researched some of them
and added some of my own.

                                        Thank you,
                                        Jim McRee  (209507097@VUVAXCOM.BITNET)

(* ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** *)

                              CONTROL SEQUENCE SUMMARY

  * For additional information on the DEC VT100 and VT102 terminals, please
    consult the VT100 USER GUIDE and VT102 USER GUIDE, published by Digital
    Equipment Corporation as part numbers EK-VT100-UG and EK-VT102-UG.


Name    Decimal Action Taken
NUL     0       Fill character; ignored on input.
ENQ     5       Transmit answerback message.
BEL     7       Ring the bell.
BS      8       Move cursor left.
HT      9       Move cursor to next tab stop.
LF      10      Line feed; causes print if in autoprint.
VT      11      Same as LF.
FF      12      Same as LF.
CR      13      Move cursor to left margin or newline.
SO      14      Invoke G1 character set.
SI      15      Invoke G0 character set.
XON     17      Resume transmission.
XOFF    19      Halt transmission.
CAN     24      Cancel escape sequence and display checkerboard.
SUB     26      Same as CAN.
ESC     27      Introduce a control sequence.
DEL     127     Fill character; ignored on input.

  * All characters less than 32 decimal which are not listed above are ignored.

(* ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** *)


  *In ANSI sequences, parameters are given as a string of ASCII digits
   ('0' - '9') seperated by semicolons.  Pn refers to a number whose value
   used directly.  Ps refers to a number used as a selector.


        Cursor Up:      Esc [ Pn A
        Cursor Down:    Esc [ Pn B
        Cursor Left:    Esc [ Pn C
        Cursor Right:   Esc [ Pn D

        Direct Addressing :  Esc [ Pn(row);Pn(col);H or
                             Esc [ Pn(row);Pn(col);f

                             ie.  (Pascal)
                                Writeln (Esc,'[',Row:1,';',col:1,';','H');

        Index:          Esc D
        New Line:       Esc E
        Reverse Line:   Esc M

        Save cursor and Attributes:     Esc 7
        Restore cursor and attributes:  Esc 8


        Cursor to end of line           Esc [ K
        Beginning of line to cursor     Esc [ 1 K
        Entire line                     Esc [ 2 K
        Cursor to end of screen         Esc [ J
        Beginning of screen to cursor   Esc [ 1 J
        Entire screen                   Esc [ 2 J

       (Some programs expect Esc [ J to always clear the entire
        screen, but this does not conform to the standard.)


        Set with        Esc [ Ps h
        Reset with      Esc [ Ps l

Mode name               Ps      Set             Reset
Keyboard action         2       Locked          Unlocked
Insertion               4       Insert          Overwrite
Send - Receive          12      Full            Echo
Line feed/New line      20      New line        Line feed
Cursor key              ?1      Application     Cursor
ANSI/VT52               ?2      ANSI            VT52
Column                  ?3      132             80
Scrolling               ?4      Smooth          Jump
Screen                  ?5      Reverse         Normal
Origin                  ?6      Relative        Absolute
Wraparound              ?7      Wrap            Truncate
Auto key repeat         ?8      Repeating       No repeat
Print form feed         ?18     Yes             No
Print extent            ?19     Full screen     Scrolling region

Keypad application      Esc =
Keypad numeric mode     Esc >


        Insert line             Esc [ Pn L
        Delete line             Esc [ Pn M
        Delete character        Esc [ Pn P
        Scrolling region        Esc [ Pn(top);Pn(bot) r


        Print screen or region  Esc [ i
        Print cursor line       Esc [ ? 1 i
        Enter auto print        Esc [ ? 5 i
        Exit auto print         Esc [ ? 4 i
        Enter print controller  Esc [ 5 i
        Exit print controller   Esc [ 4 i


        The following is a list of the available styles of printing on the
screen.  "Yes" in any column means that the option is supported by the escape
code on that line.  "No" means that the option is not supported by the escape
code on that line; however, it may, and almost certainly is, supported by
another escape sequence.

Double-height and double-width double the size of the characters in their
respective ways (ie. Double-height is twice as tall as usual).  _Line
designates underlining.  Blink is for blinking characters.  Side is the
orientation of the character.  Normal means that there is no orientation.

Top and bottom refers to the position of the character in order to make a
complete character.  The top and bottom sequences will be important if you use
the double height option.  You will need to print the line twice to get a
complete line.  The first printing will print the top part of the characters
and the second printing will print the bottom part.

Inverse refers to the condition of the character.  "No" indicates that the
character will be printed in the color it normally is printed in with its usual
backround.  "Yes" means that the character will be printed in the backround
color and the character's backround will be the color it is usually printed in.
Shade refers to the brightness of the character.  Normal is the standard
brightness of the character.  Bright is bold type.  Dark is a darker brightness
than usual.

The escape code is the command you would type before the text you want to print
to get the indicated effects.  This section was greatly expanded in version 1.1
of this file.

Double  Double
Height  Width   _Line   Blink  Side    Inverse  Shade   Escape Code
 No      No       No     No    Normal    No     Normal  [0m
 Yes     Yes      No     No    Top       No     Bright  #3[1m
 Yes     Yes      No     No    Bottom    No     Bright  #4[1m
 Yes     Yes      No     No    Top       No     Dark    #3[2m
 Yes     Yes      No     No    Bottom    No     Dark    #4[2m
 Yes     Yes      No     No    Top       No     Normal  #3[3m
 Yes     Yes      No     No    Bottom    No     Normal  #4[3m
 Yes     Yes      Yes    No    Top       No     Normal  #3[4m
 Yes     Yes      Yes    No    Bottom    No     Normal  #4[4m
 Yes     Yes      No     Yes   Top       No     Normal  #3[5m
 Yes     Yes      No     Yes   Bottom    No     Normal  #4[5m
 Yes     Yes      No     No    Top       Yes    Normal  #3[7m
 Yes     Yes      No     No    Bottom    Yes    Normal  #3[7m
 No      Yes      No     No    Normal    No     Normal  #6[0m
 No      Yes      No     No    Normal    No     Bright  #6[1m
 No      Yes      No     No    Normal    No     Dark    #6[2m
 No      Yes      Yes    No    Normal    No     Normal  #6[4m
 No      Yes      No     Yes   Normal    No     Normal  #6[5m
 No      Yes      No     No    Normal    Yes    Normal  #6[7m
 No      No       No     No    Normal    No     Bright  #7[1m
 No      No       No     No    Normal    No     Dark    #7[2m
 No      No       Yes    No    Normal    No     Normal  #7[4m
 No      No       No     Yes   Normal    No     Normal  #7[5m
 No      No       No     No    Normal    Yes    Normal  #7[7m

* Some codes have been eliminated due to a repetition of effects.  To the best
  of my knowledge, these codes are complete and correct.  If you should find
  any errors, or you find some new sequences/effects, please inform me.

* #3 and #4 behave in the same way as #3[3m and #4[4m.


Character set           G0              G1
United Kingdom (UK)     Esc ( A         Esc ) A
United States (US)      Esc ( B         Esc ) B
Graphics                Esc ( 0         Esc ) 0
Default ROM             Esc ( 1         Esc ) 1
Alternate ROM           Esc ( 2         Esc ) 2

Switch to G0/G1         Esc O           Esc N


        Set tab at current column       Esc H
        Clear tab at current column     Esc [ g
        Clear all tabs                  Esc [ 3 g


        Hard Reset                      Esc c

        Character attributes            Esc [ Ps m    Example Esc[1m  for Bold
                                    or  Esc [ Ps ; Ps ; Ps m
                0 - All attributes off
                1 - Bold on
                4 - Underscore on
                5 - Blink on
                7 - Reverse on

        Programmable LEDs               Esc [ Ps q
                0 - All LEDs off
          (1 - 4) - Turn respective LED on

        Fill screen with "E"s (test)    Esc # 8

(* ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** *)


        *Some VT100 terminal programs also understand a few other escape
         sequences than the standard VT100.  I cannot guarantee that any of
         these nonstandard codes will work with any particular terminal, but
         they may be useful if they do work.

        Transmit a file         Esc { T filenameCR   ---> CR = Carriage Return
        Receive a file          Esc { R filenameCR   ---> CR = Carriage Return
        Append to a file        Esc { A filenameCR   ---> CR = Carriage Return
        Save collected text     Esc { S
        Save collected text     Esc S

        * These sequences will probably be most useful in developing a micro
          version of a VT100 emulator or in adapting an existing one.

(* ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** ** *)


        Cursor up               Esc A
        Cursor down             Esc B
        Cursor right            Esc C
        Cursor left             Esc D
        Graphics character set  Esc F
        ASCII character set     Esc G
        Home cursor             Esc H
        Reverse line feed       Esc I
        Erase to end of screen  Esc J
        Erase to end of line    Esc K
        Print cursor line       Esc V
        Enter print controller  Esc W
        Exit print controller   Esc X
        Cursor address          Esc Y row col
        Identify                Esc Z
        Print screen            Esc ]
        Enter auto print        Esc ^
        Exit auto print         Esc -
        Alternate keypad        Esc =
        Numeric keypad          Esc >
        Enter ANSI mode         Esc <

        * Row and column numbers are single characters with a bias of 31.
          E.g., "$" means row/column 5.)


                                Vt52    ANSI and Cursor Key modes
                Arrow Key       Mode    Reset           Set
                Up              Esc A   Esc [ A         Esc O A
                Down            Esc B   Esc [ B         Esc O B
                Right           Esc C   Esc [ C         Esc O C
                Left            Esc D   Esc [ D         Esc O D


                     VT52 Mode                       ANSI Mode
        Key     Numeric         Application     Numeric         Application
        0       0               Esc ? p         0               Esc O p
        1       1               Esc ? q         1               Esc O q
        2       2               Esc ? r         2               Esc O r
        3       3               Esc ? s         3               Esc O s
        4       4               Esc ? t         4               Esc O t
        5       5               Esc ? u         5               Esc O u
        6       6               Esc ? v         6               Esc O v
        7       7               Esc ? w         7               Esc O w
        8       8               Esc ? x         8               Esc O x
        9       9               Esc ? y         9               Esc O y
        -       -               Esc ? m         -               Esc O m
        ,       ,               Esc ? l         ,               Esc O l
        .       .               Esc ? n         .               Esc O n
        ENTER   ^M              Esc ? M         ^M              Esc O M
        PF1     Esc P           Esc P           Esc O P         Esc O P
        PF2     Esc Q           Esc Q           Esc O Q         Esc O Q
        PF3     Esc R           Esc R           Esc O R         Esc O R
        PF4     Esc S           Esc S           Esc O S         Esc O S


        Esc [ c         DA:Device Attributes


        Esc Z           DECID:Identify Terminal (ANSI mode)

                        * For PC/Intercomm and some other emulators,
                          irrespective of the parameter(s) present, the
                          response is always

                                Esc [ ? 6 c

                          (i.e., a VT102)  Other DEC terminals will respond
                          according to their configuration and mode.

        Esc Z           Identify (VT52 mode)

                        * The sequence Esc / Z is always returned.

        Esc [  x   DECREQTPARM: Request Terminal Parameters

                        *  values other than 1 are ignored.  Upon
                          receipt of a  value of 1, the following
                          response is sent:


                                * Where , , , and
                                  are as for VT100s with the following

                                         Values of 5 and 6 bits per
                                                character are sent as 7 bits.

                                                These two numbers will always
                                                be the same.  9600 baud is
                                                sent for 7200 baud.

        Esc [ Ps n      DSR: Device Status Report

                        * Parameter values other than 5, 6, are ignored.
                          If the parameter value is 5, the sequence
                          Esc [ O n is returned.  If the parameter value is
                          6, the CPR: Cursor Position Report sequence
                          Esc [ Pn ; Pn R is returned with the Pn set to
                          cursor row and column numbers.

***** END *****