ASCII Code Summary Appendix F
NetScan User’s Manual F-3
ASCII Code DetailsDecimal Values 00 to 31 – ACG & UCG Descriptions
ASCII Control Codes (00 to 31)
Dec Name Description
00 Null (NUL) Space filler character. Used in output timing for some device
drivers.
01 Start of Header (SOH) Marks beginning of message header.
02 Start of Text (STX) Marks beginning of data block (text).
03 End of Text (ETX) Marks end of data block (text).
04 End of Transmission (EOT) Marks end of transmission sess ion.
05 Inquiry (ENQ) Request for identification or information.
06 Acknowledgement (ACK) “Yes” answer to questions or “ready for next transmission.” Used in
asynchronous protocols for timing.
07 Bell (BEL) Rings bell or audible alarm on terminal.
08 Backspace (BS) Moves cursor position back one character.
09 Horizontal Tab (HT) Moves curs or position to next tab stop on line.
10 Line Feed (LF) Moves cursor position down one line.
11 Vertical Tab (VT) Moves cursor position down to next “tab line.”
12 Form Feed (FF) Moves cursor position to top of next page.
13 Carriage Return (CR) Moves cursor to left margin.
14 Shift Out (SO) Next characters do not follow ASCII definiti ons .
15 Shift In (SI) Next characters revert t o ASCII meaning.
16 Data Link Escape (DLE) Used to control transmissions us ing “escape sequences.”
17 Device Control 1 (DC1) Not defined. Normally used for ON controls.
18 Device Control 2 (DC2) Usually user-defined.
19 Device Control 3 (DC3) Not defined. Normally used for OFF controls.
20 Device Control 4 (DC4) Usually user-defined.
21 Negative Acknowledgement (NAK) “No” answer to questions or “errors found, re-transmit.” Used in
asynchronous protocols for timing.
22 Synchronous Idle (SYN) Sent by as ynchronous devices when idle to insure sync.
23 End of Transmission Block (ETB) Marks block boundari es in transmission.
24 Cancel (CAN) Indicates previous transmission should be disregarded.
25 End of Medium (EM) Marks end of physical media, as in paper tape.
26 Substitute (SUB) Used to replace a character known to be wrong.
27 Escape (ESC) Marks beginning of an Escape control sequence.
28 File Separator (FS) Marker for major portion of trans m ission.
29 Group Separator (GS) Marker for submajor portion of transmission.
30 Record Separator (RS) Marker for minor porti on of transmission.
31 Unit Separator (US) Marker for most minor portion of transmission.