C1 controls

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File Format
Name C1 controls

The C1 controls are the control characters (code positions 128-159 decimal) which are defined by ISO/IEC 6429:1992 and are part of the ISO-8859 encoding. They are also part of a number of other character sets derived from ASCII. They are not often used, and in otherwise equivalent Microsoft character sets (e.g., Windows 1252) they are replaced by printing characters.

NOTE: I'm cloning this from the C0 article and saving it occasionally. There will be gross errors till I'm done. Bear with me or dive in. --Gmcgath (talk) 12:34, 30 November 2012 (UTC)

Hex Dec Abbreviation Name Description and uses
80 128 PAD Padding Character Not part of ISO/IEC 6429.
81 129 HOP High Octet Preset Not part of ISO/IEC 6429.
82 130 BPH Break Permitted Here Follows a graphic character where a line break is permitted.
83 131 NBH No Break Here Follows a graphic character where a line break is not permitted.
84 132 IND Index Moves the active position one line down.
85 133 NEL Next Line Used in transmission protocols to request acknowledgement from the other end to make sure connection is still active. In DEC TOPS-20 mainframes, usually resulted in currently-active application outputing status information to terminal.
86 134 SSA Start of Selected Area Sent as response to ENQ message, or used to positively acknowledge receipt of data or messages (as opposed to NAK).
87 135 ESA End of Selected Area On some systems, this causes a bell, buzzer, or beep to sound, or flashes inverse video to alert a system operator. The Apple II had "BELL" on the front side of the "G" key to remind users that Ctrl-G caused this sound effect.
88 136 HTS Horizontal Tabulation Set Moves back one space. Usually deletes last character (e.g., from input string), but on some old terminals it just moved backward without deleting and allowed "overstrike" effects overlaying multiple characters.
89 137 HTJ Horizontal Tabulation with Justification The typewriter "tab key", usually moving to the next tab stop as defined in the particular software being used.
8A 138 VTS Vertical Tabulation Set Move down one line. In Unix-style operating systems, it also moves to the beginning of the next line so that it can be used as a line break (newline) character, while in some other systems and terminals it just moves down without moving to the left, requiring the "CR LF" sequence to break a line.
8B 139 PLD Partial Line Down Moves to vertical tab stops; not used nearly as often as the more-common horizontal tab.
8C 140 PLU Partial Line Up Causes page to eject in printers, and may clear the screen in some terminal emulators. Sometimes used as a logical division of sections of a document.
8D 141 RI Reverse Index Moves the active position one line up.
8E 142 SS2 Single-Shift 2 Switch to alternate character set (reversed by SI). Used in various systems and terminals to set different characters (e.g., APL or Cyrillic), or change the color or font.
8F 143 SS3 Single-Shift 3 Return to normal character set (reverses operation of SO).
90 144 DCS Device Control String Signals the start of a sequence of raw data as opposed to normal printable or control characters.
91 145 PU1 Private Use 1 One of four device-control codes intended to be system-specific. This one (CTRL-Q, also known as XON) is often used to resume operations of a process, device, or output stream that has been paused with CTRL-S (XOFF).
92 146 PU2 Private Use 2 Another device-control code; not used as much as DC1 and DC3.
93 147 STS Set Transmit State The third of the device-control codes; this one (CTRL-S, also known as XOFF) is often used to pause processes, devices, or output streams, with CTRL-Q (XON) resuming them (though in some cases, any keypress causes output to resume).
94 148 PCH Cancel Character The fourth device-control code; not used as much as DC1 or DC3. In DEC TOPS-20 mainframes, usually resulted in output of system status to terminal.
95 149 MW Message Waiting In transmission protocols, indicates a failure requiring a re-send, or a negative response to a query of whether the process is ready to proceed.
96 150 SPA Start of Protected Area Signals that a correction may now be received in synchronous transmission protocols.
97 151 EPA End of Protected Area Marks the end of a block of data divided into blocks for transmission.
98 152 SOS Start of String Cancels an operation and signals that previously-sent data can be disregarded.
99 153 SGCI Single Graphic Character Introducer Marks the end of a physical medium such as a data-storage tape.
9A 154 SCI Single Character Introducer Used to mark the spot where garbled, missing, or incomplete characters were received due to transmission errors, or various other uses involving place-holder characters. This character (Ctrl-Z) is also used by MS/PC-DOS to mark the end of a file or input stream, calling it EOF (although CTRL-D, EOT, would have been more standards-compliant and is used by Unix-style OSs for this purpose; however, some DEC operating systems used the CTRL-Z convention and this is what was followed by PC-DOS).
9B 155 CSI Control Sequence Introducer Mapped onto the ESC key on keyboards, this usually signals a user attempting to exit a menu or mode. It is also commonly used in printer and terminal control protocols to signal the beginning of a special "escape sequence" where immediately-following characters are interpreted as commands.
9C 156 ST Operating System Command Introduces an operating system command, which is terminated by ST (0X96).
9D 157 OSC Group Separator The second of four separator characters, subordinate to FS, but higher-level than RS and US.
9E 158 PM Privacy Message Introduces a privacy message, which is terminated by ST (0X96).
9F 159 APC Application Program Command Introduces an application program command, which is terminated by ST (0X96).
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