Control Codes
Most of the time you don’t give this code system a thought. If you
press A on the keyboard, the computer sends the code to the printer
and the letter A is printed. However, some printer codes, like the one
for a vertical tab, do not have a key on the keyboard.
These are the ASCII codes with values of less than
32.
These codes
are called control codes because they control the operation of the
printer. These characters are not displayed on your screen and aren’t
printed as a character by your printer.
ESCape Sequences
There are not enough control codes for all the advanced features of
modern printers, so multiple-code control sequences have been devel-
oped. All of these control sequences begin with the control code AS-
CII 27, which is called escape. These sequences can have more than
one code following Escape, depending on the command. (In this
manual, ESCape is written as ESCape or ESC, depending on whether
it’s being used in a sentence or as a control code. You might also see it
written as (ESC) in other manuals.)
The ESCape code changes the interpretation of the codes that fol-
low it-they are interpreted as part of a printer command. For exam-
ple, if the
FX-286
receives the decimal code
52,
it prints the numeral
4
because 52 is the ASCII code for that number. If, however, the printer
receives a 27 just before the 52, it turns on the italic mode, because
ESCape
"4"
is the
FX-286’s
code for italic printing.
This same command could also be written with the "4" in place of
the 52. As noted at the beginning of Appendixes G and J, many
ESCape sequences can use letters or numbers enclosed in quotation
marks. These letters or numbers can be used in place of the decimal or
hexadecimal values as long as they’re placed in quotes. There’s no
functional difference between the two systems, but you might find the
letters and numbers easier to remember.
Demonstration Programs
To help you understand control codes and ESCape sequences and to
enable you to see the
FX-286
features in action, this manual includes
demonstrations in the BASIC programming language. Although you
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