3. EMULATION DETAILS; 3.1. Ignored Commands; 3.2. Resolution- Page 324

CHAPTER 7 IBM PROPRINTER - 6 

3.

EMULATION DETAILS 

The following points should be borne in mind when running the HL Series printers in IBM Proprinter XL 
mode. 

3.1.

Ignored Commands 

A few IBM Proprinter XL commands have reduced effect, or no effect at all.  In some cases this is due to 
the physical nature of an HL Series printer.  These commands are as follows.  The 

BEL

 control code 

(ASCII 7) which is used to sound the Proprinter's bell, is ignored.  The 

DC3

 control code (ASCII 23), 

used to disable the Proprinter, is also ignored.  The 

Esc Y

 escape sequence, which enables double-speed, 

double-density graphics mode has no effect on the printing speed, as HL Series printers always operate as 
fast as they can.  Hence the 

Esc Y

 has the same effect as the 

Esc L

 (enable double-density graphics 

mode) sequence. 

3.2.

Resolution 

The resolution of the HL Series printers is 600 dots per inch.  Some IBM Proprinter commands use 
fractions of an inch that not exactly divisible by 600, for example 

Esc 0

 sets line spacing to 1/8" of an 

inch.  Similarly, the Proprinter graphics commands specify resolutions of 72, 120 and 240 dots per inch.  
When a graphic cannot be represented exactly at 600 dots per inch the printer prints the closest possible 
approximation to the specified image using 600 dots per inch. 

3.3.

Character Set selection 

Using software commands you can select IBM character set I, IBM character set II or the IBM All 
Character Code table.  Using the printer control panel you can select a number of other character sets 
depending on the printer model, consult the User's Guide to see if this emulation is supported and for a 
description of how to do this.  All available character sets are shown in the IBM Proprinter XL mode 
section of the appendix at the end of this manual.   

3.4.

Controlling the Printer 

Commands are invoked using either control codes or escape sequences.  You can send them to the printer 
as part of a program,  using the same command that you would use to print a text string on the printer.  
For example, in BASIC you would use the LPRINT command. 

3.5.

Control Codes 

Control codes are ASCII codes that tell the printer to perform a particular function  such as a line feed.  
Send a control code to the printer by sending the same type of instruction you would use to print a 
character using its ASCII code number.  For example,  the ASCII code for a form feed is 12,  so to get 
the printer to perform a form feed use the following BASIC statement: 

LPRINT CHR$(12); 

The CHR$ operator is normally used to convert an ASCII code into its corresponding character. 

3.6.

Escape sequences 

Escape sequences tell the printer which Proprinter function to perform.  An escape sequence consists of 
the ESC character followed by one or more characters which define the operation to be performed.  Send 
an escape sequence to the printer by sending the same type of instruction you would use to print 
characters using their ASCII codes.  Some escape sequences require parameter values or data following 
them, for example, commands which turn a particular feature on and off and commands for downloading 
character descriptions to the printer or for printing graphic images.  Numerical parameter data, too, is sent 
to the printer as if it were a character code to be printed.  For example, to set the left and right margin 
settings to be at 10 and 70 columns across the page the required escape sequence is 

Esc X 10 70

.  In 

BASIC this would be: 

LPRINT CHR$(27); CHR$(88); CHR$(10); CHR$(70);