User guide

Printer Controlling
Incorporated Commands
A printer command code is usually a series of otherwise normally printable
characters inserted in the data string sent to the printer. To make the printer
understand which characters are to be interpreted as command and which as
printable characters, there is a simple convention: all "characters" that have,
according to the character table, a decimal value less than 32 are interpreted as
control codes. Some of them result in printer action when they are received,
others do not (see Appendix F).
There is also a special command ESCAPE (decimal code 27, named ESC)
which is used by most printer emulations to open a command sequence (also
known as ESCAPE sequence). It is followed by one or more additional
characters, which serve as identifiers and parameters, belonging to the range of
printable characters or control codes available (see Appendix E).
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