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DEC LA120 EMULATION

Introduction

This section describes the control codes and escape sequences comprising DEC LA120 emulation.
This emulation may be selected by setting “Emulation” to “LA120” in the interface setup menu, or via
software with the

ESC ESC 5

sequence. While this emulation is selected, control codes and escape

sequences from other emulations are not available.

Control codes and escape sequences are used to control printer operation. An ASCII control code is a
single character in the range 00 hex through 1F hex, and 7F hex. The

ESC

(Escape) control code (1B

hex) is used to introduce character strings called escape sequences, which provide an extension of the
commands available with ASCII control codes.

The LA120 control codes and escape sequences follow the standards of the ANSI X3.64 specification.
Many ANSI escape sequences begin with a two character Control Sequence Introducer (CSI), Escape
Left Square Bracket (

ESC [

, 1B 5B hex). If 8-bit data is selected via control panel setup, these two

characters may be replaced by a single character CSI, 9B hex. The sequences are always documented
in this section with the two character CSI (

ESC [

), because this format seems to be much more

common, and works equally well with 7-bit or 8-bit data.

Some escape sequences accept one or more numeric parameters. A numeric parameter is a decimal
number represented by a string of ASCII decimal digits (“0” through “9”). Leading zeros may be
supplied, but are not necessary. Due to implementation constraints, the largest value that can be
accepted is decimal 255. Larger values will be treated as zero. Omitting a numeric parameter is
equivalent to supplying a value of zero.

If a sequence accepts one numeric parameter, it will be represented as “

”. If a sequence accepts more

than one numeric parameter, they will be represented as “

;

; ...

”. Note that multiple numeric

parameters are separated by a semicolon.

Most LA120 escape sequences will assume one of the following formats:

ESC f

(no numeric parameters)

ESC n f

(one numeric parameter)

ESC n1; n2; ... nx f

(two or more numeric parameters)

The “

” at the end of the escape sequence represents the final character. It terminates the sequence, and

specifies the function to be performed.

Spaces are used when documenting escape sequences to increase readability. The spaces within the
sequences are for readability only; they are not part of the sequences themselves. Characters that
appear in

italics

(such as “

” and “

” above) are not sent to the printer as is; they are used as a place

holder indicating that some value must be supplied.

Multiple character strings without intervening spaces typically represent control codes. For example,

is the Backspace control code (08 hex), not the two characters “B” and “S” (42 and 53 hex). An

ASCII Control Code Table is provided on page 139 for your convenience. If you have any doubt
about how to interpret a documented control code or escape sequence, refer to the hex representation in
the provided example. This should clarify any ambiguity. The examples may also be helpful when
analyzing a hex dump (see Hex Dump chapter) printed by the printer.