Printronix ANSI Printer manual Escape Control Codes Overview, Format For Control Code Descriptions

Format For Control Code Descriptions

Escape Control Codes Overview

Printer capability is greatly increased by the use of escape control code sequences. Escape sequences always begin with the ASCII escape sequence introducer, ESC (hex 1B). Many of the ASCII control codes described in this chapter are escape sequences.

IMPORTANT An Escape code can occur anywhere in the data stream and is acted

upon immediately if it precedes a valid command.

An ESC sequence introducer in the data stream signals the printer to wait for special instructions, even if it is ready and printing. The character codes following the ESC character tell the printer what to do.

NOTE: For readability, code sequences appear in this manual with spaces inserted between command elements. Do not insert spaces between code characters when you are programming unless the ASCII space character (SP) is part of a code sequence. For example, a code sequence printed in this manual as ESC [ 1 is programmed as ESC[1.

An escape sequence uses two or more bytes to define a specific printer control function. The format for an escape sequence is

ASCII	ESC	X	p
Hex	1B	00 - 5F	0 - FF
	Escape	Character(s)	Numerical
	Sequence		parameter(s)
	Introducer

After the ESC character are one or more characters which indicate the action of the control code. One or more numerical parameters may in turn follow these characters. For example, the sequence ESC [ p g tells the printer to clear all horizontal tabs if p is a 3, or to clear all vertical tabs if p is a 4.

If the characters following the ESC code are not within the defined ranges, or if they are within the defined ranges but are not recognized as a function of this printer, the entire sequence is ignored.

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