Epson SQ-2000, Руководство по эксплуатации

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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 line feed, do not have a key on the keyboard.
These are the ASCII codes with values of less than 33. 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.
The ASCII codes 0 through 32 have commonly used abbrevia-
tions for their names, such as <LF> for a line feed. These con-
trols are listed in Appendix A.
ESCape Sequences
There are not enough control codes for all of the advanced
features of modem printers, so multiple-code control sequences
have been developed. All of these control sequences begin with
the control code ASCII 27, which is called
Escape.
(In this manual
it is abbreviated as <ESC>.) These sequences can have more
than one code following Escape, depending on the command.
The ESCape code changes the interpretation of the codes that
follow it - they are interpreted as part of a printer command. For
example, if the SQ-2000 receives the number 52, it prints the
numeral 4 because 52 is the ASCII code for that letter. However, if
the printer receives a 27 just before the 52, it turns on the italic
mode, because ESCape “4” is the SQ-2000’s code for italic print-
ing, as shown in Appendix A.
This same command could also be written with “4” (including
the quotation marks) in place of the 52. Many ESCape sequences
are written with 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.
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