ansix364.doc

ANSI Standard (X3.64) Control Sequences for Video Terminals and Peripherals

For instance, a format effector that moves the "active position" (the 
cursor or equvalent) one space to the left would be useful when you want to 
create an overstrike, a compound character made of two standard characters 
overlaid. Control-H, the Backspace character, is actually supposed to be a 
format effector, so you can do this. But many systems use it in a 
nonstandard fashion, as an editor function, deleting the character to the 
left of the cursor and moving the cursor left. When Control-H is assumed to 
be an editor function, you cannot predict whether its use will create an 
overstrike unless you also know whether the output device is in an "insert 
mode" or an "overwrite mode". When Control-H is used as a format effector, 
its effect can always be predicted. The familiar characters carriage 
return, linefeed, formfeed, etc., are defined as format effectors. 
 
v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v 
^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^ 
 
ANSI X3.64 Mode-Changing Parameters for use with the 
           Select Mode (SM) and Reset Mode (RM) functions 
 
    Parameter           Mode          Mode Function 
    Characters          Mnemonic 
 column/    graphic 
  row       repres. 
---------------------------------------------------------------------------- 
3/0           0                       an error condition 
3/1           1          GATM         guarded-area transfer mode 
3/2           2          KAM          keyboard action mode 
3/3           3          CRM          control representation mode 
3/4           4          IRM          insertion/replacement mode 
3/5           5          SRTM         status-reporting transfer mode 
3/6           6          ERM          erasure mode 
3/7           7          VEM          vertical editing mode 
3/8           8                       reserved for future standardization 
3/9           9                       reserved for future standardization 
3/10          :                       reserved separator for parameters 
3/11          ;                       Standard separator for parameters 
3/12          <                       reserved for private (experimental) use 
3/13          =                       reserved for private (experimental) use 
3/14          >                       reserved for private (experimental) use 
3/15          ?                       reserved for private (experimental) use 
3/1  3/0      10         HEM          horizontal editing mode 
3/1  3/1      11         PUM          positioning unit mode 
3/1  3/2      12         SRM          send/receive mode 
3/1  3/3      13         FEAM         format effector action mode 
3/1  3/4      14         FETM         format effector transfer mode 
3/1  3/5      15         MATM         multiple area transfer mode 
3/1  3/6      16         TTM          transfer termination mode 
3/1  3/7      17         SATM         selected area transfer mode 
3/1  3/8      18         TSM          tabulation stop mode 
3/1  3/9      19         EBM          editing boundary mode 
3/1  3/10     1:                      reserved separator for parameters 
3/1  3/11     1;                      Standard separator for parameters 
3/1  3/12     1<                      error condition--unspecified recovery 
3/1  3/13     1=                      error condition--unspecified recovery 
3/1  3/14     1>                      error condition--unspecified recovery 
3/1  3/15     1?                      error condition--unspecified recovery 
3/2  3/0      20         LNM          linefeed/newline mode (not in ISO 6429) 
3/2  3/1      21 
 .            . 
 .            .                       reserved for future standardization 
 .            . 
3/9  3/9      99 
 
3/12 3/0      <0 
 .            . 
 .            .                       reserved for private (experimental) use 
 .            . 
3/15 3/15     ?? 
 
v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v 
^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^ 
 
NOTES ON THE DEC VT100 IMPLEMENTATION 
 
In the case of the popular DEC VT100 video-terminal implementation, 
the only mode that may be altered is the linefeed/newline (LNM) mode. 
Other modes are considered permanently set, reset, or not applicable 
as follows: 
 
     Set:   ERM 
     Reset: CRM, EBM, FEAM, FETM, IRM, KAM, PUM, SRTM, TSM 
     N/A:   GATM, HEM, MATM, SATM, TTM, VEM 
 
Control sequences implemented in the VT100 are as follows: 
 
     CPR, CUB, CUD, CUF, CUP, CUU, DA, DSR, ED, EL, HTS, HVP, IND, 
     LNM, NEL, RI, RIS, RM, SGR, SM, TBC 
 
plus several private DEC commands. 
 
Erasing parts of the display (EL and ED) in the VT100 is performed thus: 
 
     Erase from cursor to end of line           Esc [ 0 K    or Esc [ K 
     Erase from beginning of line to cursor     Esc [ 1 K 
     Erase line containing cursor               Esc [ 2 K 
     Erase from cursor to end of screen         Esc [ 0 J    or Esc [ J 
     Erase from beginning of screen to cursor   Esc [ 1 J 
     Erase entire screen                        Esc [ 2 J 
 
The VT100 responds to receiving the DA (Device Attributes) control 
 
     Esc [ c    (or Esc [ 0 c) 
 
by transmitting the sequence 
 
     Esc [ ? l ; Ps c 
 
where Ps is a character that describes installed options. 
 
The VT100's cursor location can be read with the DSR (Device Status 
Report) control 
 
     Esc [ 6 n 
 
The VT100 reports by transmitting the CPR sequence 
 
     Esc [ Pl ; Pc R 
 
where Pl is the line number and Pc is the column number (in decimal). 
 
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^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^v^ 
 
The complete document describing the standard,  "ANSI X3.64-1979: 
Additional Controls for Use with the American National Standard 
Code for Information Interchange," can be ordered for $13.50 (plus 
$4 postage) from 
 
     Standards Sales Department 
     American National Standards Institute 
     1430 Broadway 
     New York, NY 10018 
     212/354-3300 
 
It's best to read the full standard before using it. It also helps 
to have copies of the related standards "X3.4-1977: American 
National Standard Code for Information Interchange" (the ASCII 
standard) and "X3.41.1974: Code-Extension Techniques for Use with 
the 7-Bit Coded Character Set of American National Standard for 
Information Interchange." 
 
See also the chapter "Using Extended Screens and Keyboard Control" 
in the IBM PC-DOS manuals (versions 2.0, 2.1, and 3.0), especially 
for the coding for character attributes. 
 
The specification for the DEC VT100 is document EK-VT100-UG-003, 
available for $13.00 prepaid from: 
 
     Digital Equipment Corporation 
     Accessories and Supplies Group 
     POB CS-2008 
     Nashua, NH 03061 
 
(Copyright 1984 BYTE Publications, subsidiary of McGraw-Hill Inc.) 
(Permission granted to reproduce for noncommercial uses.) 
(This file prepared by Richard S. Shuford.)