CAN (Cancel): A control character used to indicate that the data with which it is sent is in error
or is to be disregarded.
EM (End of Medium): A control character associated with the sent data which may be used to
identify the physical end of the medium, or the end of the used, or wanted, portion of information
recorded on a medium. (The position of the character does not necessarily correspond to the
physical end of the medium.)
SUB (Substitute): A character that may be substituted for a character which is determined to be
invalid or in error.
ESC (Escape): A control character intended to provide code extension (supplementary
characters) in general information interchange. The Escape character itself is a prefix affecting
the interpretation of a limited number of succession following characters. ESC is usually ter-
minated by a Shift In character(s).
FS (File Separator), GS (Group Separator), RS (Record Separator) and US (Unit Separator). These
information separators may be used within data in optional fashion, except that their order of
precedence relationship shall be: FS is the most inclusive, then GS, then RS. and US is least in-
clusive. (The content and length of a File, Group, Record, or Unit are not specified.)
DEL (Delete): This character is used primarily to "erase" or "obliterate" erroneous or unwanted
characters in perforated tape. (In the strict sense, DEL is not a control character.)
c. Graphic Characters
SP (Space): A normally nonprinting graphic character used to separate words. It is also a format
effecter" which controls the movement of the printing position, one printing position forward (ap-
plicable also to visual display devices).
(Diamond): A noncoded graphic which shall be printed by a printing device to denote the
sensing of an error when such an indication is required. As an interim standard, an asterisk (')
may be used for this function.
(Heart): A noncoded graphic which may be printed by a printing device instead of the sym-
bols for the control characters shown in columns 0 and 1 in table E-1.