“Control A” codes (a.k.a. ^A codes) are terminal control sequences embedded in Synchronet text and menu display files.
Ctrl-A codes are primarily used in place of ANSI X3.64 terminal escape sequences to control terminal text attribute (e.g. color) combinations and perform some cursor positioning and other advanced features (not available with ANSI escape sequences).
The advantage that Ctrl-A codes have over ANSI escape sequences is that they are easily stripped out or converted by the Terminal Server of the BBS software to automatically meet the capabilities of the remote user's terminal. There are additional capabilities in Ctrl-A codes that go beyond the realm of terminal control and ANSI escape sequences.
The Ctrl-A character was chosen because it's a control character not often found in displayable text files or expected to be rendered in a consistent manner on all terminals. And “A” is for “Attribute”.
Ctrl-A codes may be included in most text files displayed to users of the Synchronet Terminal Server as well as messages posted in message bases, extended file descriptions, and other places where some colored text can give users the opportunity to better express themselves.
Ctrl-A codes are 2-character sequences which begin with a Ctrl-A (ASCII 1) character (hence the name) and are followed by a single character (case insensitive) which determines the operation to be performed. The only exception to this 2-character sequences is the Ctrl-A
“filename code, which takes a filename as an argument and the filename is considered part of the sequence and not displayed.
It can sometimes require a special purpose text editor to actually enter a Ctrl-A character into a text file. Some editors may require a special key sequence or use of a menu option to enter a Ctrl-A character into a file. The graphical representation of the character may be a happy face or any other non-alphanumeric symbol that the editor chooses to render to represent that character code. There are @-Codes for the equivalent of many of the Ctrl-A codes, so may consider using them if they are more convenient for your text editor of choice.
text.dat and possibly some other files, Ctrl-A characters may be entered using the C escape sequence:
The ANS2ASC utility may be used to convert files encoded with ANSI X3.64 terminal escape sequences (e.g.
*.ans) into Ctrl-A encoded output and the ASC2ANS utility can be used to perform the opposite operation (useful for editing Ctrl-A encoded files (e.g.
*.asc) with an ANSI-BBS screen editor).
The following table is a list of Color Ctrl-A codes and their purpose:
The following table is a list of Attribute Ctrl-A codes, and a brief description of each code's usage:
|High|| ||High Intensity (bright)|
|Normal|| ||No Special Attributes (Normal)|
|Optimized Normal|| ||Only sends sequence if High Intensity, Blinking, or Background attribute is set (or pop attributes if pushed)|
|Optimized Normal|| ||Only sends sequence if Blinking or Background attribute is set|
The following table is a list of Terminal Control Ctrl-A codes, and a brief description of each code's usage:
|Pause|| ||Display a Pause (Hit a key) Prompt|
|Pause Reset|| ||Reset the line counter for the auto screen-pause|
|Delay|| ||Delay for one tenth of a second|
|Delay|| ||Delay for one half second|
|Delay|| ||Delay for two seconds|
|Cls|| ||Clear the screen|
|Home|| ||Home the cursor|
|Clreos|| ||Clear to end of screen (leave cursor in current position)|
|Clreol|| ||Clear to end of line (leave cursor in current position)|
|Bckspc|| ||Send a non-destructive backspace character (Ctrl-H) - Cursor Left|
|CR|| ||Send a carriage return character (Ctrl-M) - Cursor to Beginning of Line|
|LF|| ||Send a line feed character (Ctrl-J) - Cursor Down|
|Push Attr|| ||Save current attributes into attribute LIFO stack|
|Pop Attr|| ||Restore attributes from stack (or Optimized Normal, if no attributes saved/pushed)|
|Cursor Right||128-255||Move cursor to the right (code-127) characters|
The following table is a list of Macro Ctrl-A codes, and a brief description of each code's usage:
|Date|| ||Display the current system date (in “MM/DD/YY” or “DD/MM/YY” format)|
|Time|| ||Display the current system time (in “HH:MM am” or “HH:MM:SS” format)|
|Ctrl-A|| ||Send an actual Ctrl-A (ASCII 1) character|
The following table is a list of Advanced Ctrl-A codes, and a brief description of each code's usage:
|Sync|| ||Synchronize output with remote system|
|EOF|| ||End of displayable text in this file|
|Embed File|| || Display contents of filename from your
Synchronet also supports Ctrl-A codes used to hide text from users not meeting certain security criteria (i.e.: Security Level or Flags from Flag Set #1).
The following table is a list of Security Ctrl-A codes, and a brief description of each code's usage:
|Ctrl-A thru Ctrl-Z||Only display the following text to users with the corresponding flag A through Z turned on (from Flag Set #1)|
|Toggle the text display off/on for users of less than level 10|
|Toggle the text display off/on for users of less than level 20|
|Toggle the text display off/on for users of less than level 30|
|Toggle the text display off/on for users of less than level 40|
|Toggle the text display off/on for users of less than level 50|
|Toggle the text display off/on for users of less than level 60|
|Toggle the text display off/on for users of less than level 70|
|Toggle the text display off/on for users of less than level 80|
|Toggle the text display off/on for users of less than level 90|
|Restore the displaying of text to ALL users|