ASCII: Acronym for American Standard Code for Information Interchange. The standard code used for information interchange among data processing systems, data communications systems, and associated equipment in the United States. The ASCII character set contains 128 coded characters. Each ASCII character is a 7-bit coded unique character; 8 bits when a parity check bit is included. The ASCII character set consists of control characters and graphic characters. When considered simply as a set of 128 unique bit patterns, or 256 with a parity bit, dis-associated from the character equivalences in national implementations, the ASCII may be considered as an alphabet used in machine languages. The ASCII is the U.S. implementation of International Alphabet No. 5 (IA No. 5) as specified in CCITT Recommendation V.3.
|1||1||SOH||(start of heading)||33||21||!||65||41||A||97||61||a|
|2||2||STX||(start of text)||34||22||"||66||42||B||98||62||b|
|3||3||ETX||(end of text)||35||23||#||67||43||C||99||63||c|
|4||4||EOT||(end of transmission)||36||24||$||68||44||D||100||64||d|
|10||A||LF||(NL line feed, new line)||42||2A||*||74||4A||J||106||6A||j|
|12||C||FF||(NP form feed, new page)||44||2C||,||76||4C||L||108||6C||l|
|16||10||DLE||(data link escape)||48||30||0||80||50||P||112||70||p|
|17||11||DC1||(device control 1)||49||31||1||81||51||Q||113||71||q|
|18||12||DC2||(device control 2)||50||32||2||82||52||R||114||72||r|
|19||13||DC3||(device control 3)||51||33||3||83||53||S||115||73||s|
|20||14||DC4||(device control 4)||52||34||4||84||54||T||116||74||t|
|21||15||NAK||(do not acknowledge)||53||35||5||85||55||U||117||75||u|
|23||17||ETB||(end of transmission block)||55||37||7||87||57||W||119||77||w|
|25||19||EM||(end of medium)||57||39||9||89||59||Y||121||79||y|
Hex Number System
Two-Byte, 7 bit ASCII table is shown above.
An additional bit may also be sent [bit 8] to define parity.
ANSI INCITS 4-1986
[Information Systems - Coded Character Sets - 7-Bit American National Standard Code for Information Interchange (7-Bit ASCII)]
[Basic Control Language (BCL), an ASCII Data Exchange Specification for Computer Numerical Control Manufacturing]
ANSI: American National Standards Institute
ASCII codes 0 to 31 [decimal] are control codes. The meaning of the
Mnemonics listed in the table are provided below.
ASCII codes 31 to 127 [decimal] are the standard ASCII characters, printable.
The Extended ASCII character set, 128 to 255 [decimal] is not addressed on this page. [Developed by using the ALT key]
Backspace. Indicates movement of the printing mechanism or display cursor backwards in one position.
Horizontal Tabulation. Indicates movement of the printing mechanism or display cursor forward to the next preassigned 'tab' or stopping position.
Line Feed. Indicates movement of the printing mechanism or display cursor to the start of the next line (one line down).
Vertical Tabulation. Indicates movement of the printing mechanism or display cursor to the next of a series of preassigned printing lines.
Form Feed. Indicates movement of the printing mechanism or display cursor to the starting position of the next page, form, or screen. Also page eject.
Carriage Return. Indicates movement of the printing mechanism or display cursor to the starting position (left) of the current line.
Start of Heading. Used to indicate the start of a heading which may contain address or routing information.
Start of Text. used to indicate the start of the text and so also indicates the end of the heading.
End of Text. Used to terminate the text which was started with STX. End of Transmission indicates the end of a transmission which may have included one or more 'texts' with their headings.
End of Transmission Block. Indicates the end of a block of data for communication purposes. It is used for blocking data where the block structure is not necessarily related to the processing format.
Enquiry. A request for a response from a remote station. It may be used as a "who are you?" request for a station to identify itself. Also called WRU; Who Are You
End of Transmission. No additional data follows in the message
Acknowledge. A character transmitted by a receiving device as an affirmation response to a sender. It is used as a positive response to polling messages.
Negative Acknowledgment. A character transmitted by a receiving device as a negative response to a sender. It is used as a negative response to polling messages.
Synchronous/Idle. Used by a synchronous transmission system to achieve synchronization. When no data is being sent a synchronous transmission system may send SYN characters continuously.
File Separator, if another file is about to be transmitted.
Group Separator, if another group of data is about to be transmitted.
Unit Separator. Information separators to be used in an optional manner except that their hierarchy shall be FS (the most inclusive) to US (the least inclusive).
Null. No printable character, which is always ignored. Used for filling in time or filling space on tape when there is no data.
Bell. Used when there is need to call human attention. It may control an alarm or attention devices. However I never seen a bell on any printer I've ever had
Shift Out. Indicates that the code combinations which follow shall be interpreted as _outside_ the standard character set until an SI character is reached.
Shift In. Indicates that the code combinations which follow shall be interpreted according to the standard character set.
Data Link Escape. A character which shall change the meaning of one or more contiguously following characters. It can provide supplementary controls or permits the sending of data characters having any bit combination.
Device Controls. Characters for the control of ancillary devices or special terminal features.
Cancel. Indicates that the data which precedes it in a message or block should be disregarded (usually because an error has been detected).
End of Medium. Indicates the physical end of a card, tape, paper or other
medium, or the end of the required or used portion of the medium.
Of course cards are no longer used.
Substitute. Substituted for a character that is found to be erroneous or invalid. Substitute the next character is from an alternate character set
Escape. A character intended to provide code extension in that it gives a specified number of contiguously following characters an alternate meaning. The next character is interpreted as other than text.
Space. A non-printing character used to separate words, or to move the printing mechanism or display cursor forward by one position.
Delete. As in delete a character.