Xante Accel a Writer 812 Manual page 252

Introduction
Your printer comes configured with PostScript as the current printer
language mode. If you use the printer with the serial or parallel
interfaces and send HP PCL 5 files in addition to PostScript files,
you may want to set the printer to AIS (Automatic Interface
Switching) mode. See "PostScript and Emulations" in chapter 5 for
details.
Note: AIS is for switching between PostScript and HP PCL 5
modes only.
HP PCL 5 Command Syntax
Before listing supported HP PCL 5 commands, the syntax of the
commands, or escape sequences, should be explained. The following
is the syntax of an HP PCL 5 escape sequence:
<esc><cc>[<gc>][<p1><c1>[...<pn><cn>][<data>]
<esc>
<cc>
<gc>
________ Supported HP PCL 5 and HP-GL 7475A Commands A-3
The <esc> refers to the escape character and is a
decimal value of 27. To enter an <esc> from a
PC, hold the Alt key down and type '027' on the
numeric keypad.
This refers to the command code and it can fall
between '0' and '~' in the ASCII table. When
the command code is entered, the escape
sequence will use only two bytes and includes
the <esc> and <cc> only.
This refers to the group code and is used with
commands that require additional parameters.
The <gc> can be either alphabetic or numeric.