Measurement Computing Micro 488/EX rev.2.1 - Manual (Page 75)

Section 5 Command Descriptions
5.5
CR The carriage return character ($13, &H0D).
LF The line feed character ($10, &H0A).
'X Any printable character. The apostrophe is
immediately followed, without any
intervening spaces, by a single character
which is taken to be the character specified.
5.2.1.4 ASCII Character Strings
data An arbitrary string of characters. None of the
special forms given above ($char, CR, LF,
or 'X) are used. For example, CRLF as data
is taken as the letters, "C", "R", "L", and "F",
not as carriage return line feed.
'data' An arbitrary string of characters enclosed in
apostrophes (') or quotes(").
5.2.1.5 Terminators
term Any single character, specified as CR, LF,
'X
, or $char as described previously. Part
of terminator sequence used to mark the end
of lines of data and commands.
[ term] An optional term character. term[term]
means that one or two terminators may be
specified.
EOI The IEEE bus End-Or-Identify signal. When
asserted during the transfer of a character,
EOI signals that that character is the last in
the transfer. On input, EOI, if specified,
causes the input to stop. On output, EOI
causes the bus EOI signal to be asserted