ASCII=American Standard Code for Information Interchange
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 (ie 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.
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.
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.
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 Acknowledgement. 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 synchronisation. When no data is being sent a synchronous transmission system may send SYN characters continuously.
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.
Information separators to be used in an optional manner except that their heirarchy shall be FS (the most inclusive) to US (the least inclusive).
Null. No character. 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 alarm or attention devices.
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.
DC1, DC2, DC3, DC4
Device Controls. Characters for the control of ancillary devices or special terminal features.
Cancel. Indicates that the data which preceeds 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 or other medium, or the end of the required or used portion of the medium.
Substitute. Substituted for a character that is found to be erroneous or invalid.
Escape. A character intended to provide code extension in that it gives a specified number of contiguously following characters an alternate meaning.
Space. A nonprinting character used to separate words, or to move the printing mechanism or display cursor forward by one position.
Delete. Used to obliterate unwanted characters (for example, on paper tape by punching a hole in _every_ bit position).