Creating PDT Files for Epson Emulation Printers

ID: Q248816

The information in this article applies to:

Microsoft SNA Server, versions 3.0 (all SP), 4.0, 4.0 SP1, 4.0 SP2, 4.0 SP3, 4.0 U.S. SP1

SUMMARY

Some printers, especially dot-matrix printers, do not support PCL command streams, which require a different approach to creating and modifying PDFs (Printer Definition File) used in making PDTs (Printer Definition Table). This article provides the steps to create a PDT to support Epson mode, which is common to many dot-matrix printers.

MORE INFORMATION

In many cases, the dot-matrix printer is used for report and label generation using preprinted forms, so accurate placement of characters is critical. The most important settings are CPI (Characters Per Inch), which is the horizontal spacing, LPI (Lines Per Inch), which is the vertical spacing of the lines, and lines per page or page length. Also keep in mind, that most dot-matrix printers have settings for default form size, LPI, CPI and font. When you create a PDF try to keep it simple by changing only those items which are not defaulted in the printer. The use of the Generic/Text only driver delivers an ASCII stream of characters to the printer with no print formatting.

Steps to Design a PDF:

Obtain a sample of a properly printed form, using a ruler to measure the LPI, CPI, form width and length. Accuracy is very important at this stage. Note that fax transmission may alter the size, request that the end user measure as well. Many printers can be set to Hex Print, which prints all the data and codes to evaluate the control codes being sent.

Note the font being used; is it 6 point, 10 point, Draft Quality, or NLQ (near letter quality)?

Verify the default settings of the printer. Most printers have a facility to print out all the settings. Compare the needed settings to the default settings and only change the necessary parameters.

If the job fits the default settings of the printer, select the Generic/Text only driver, as it simply passes an ASCII data stream to the printer with the printer formatting the data; no PDT is used at all.

If the LPI differs, modify the LL6 and LL8 commands in the PDT and select the correct setting on the 3270 tab of the print session in SNA Server Manager. SNA Server sends the LL6 or LL8 settings at the start of a job after the START_JOB commands have been sent, overwriting whatever may have been sent in the START_JOB. Settings other than 8 or 6 LPI are supported. See the documentation for more information.

If the form size differs, use either the lines per page or form size command in the START_JOB. Better yet, if the form to be configured is the only form used on the printer, change the default form size on the printer itself.

If the CPI needs to be changed, set the appropriate value in the START_JOB. Typical values are 10 CPI or 12 CPI.

If the font needs to be changed, research the fonts available on the printer, and then add the appropriate code to the START_JOB line.

The idea is to keep modifications as slight as possible.

Example:

The following example lists the settings to place in a PDF file for 6 LPI, 10 CPI, 8.5 inch forms on an Okidata printer or Tally printer using Epson FX100 emulation:

The following changes and additions were made:

10 CPI = 1B 50
06 LPI = 1B 32 8.5 inch form = 1B 43 33 (The command sequence is 1B 43 n, n is the number of lines in hex to make the form. 51 lines are needed (8.5 inch form x 6 LPI=51 lines per form). 51 decimal=33 hexadecimal so the sequence becomes 1B 43 33.)

A highly edited example of a PDF is as follows:


/*****************************************************************************/ 
/*                                                                           */ 
/* Printer Definition File for Epson Emulation Printers                      */ 
/*                                                                           */ 
/*****************************************************************************/ 
LL6              EQU 1B 32            /* set line length 6 lines per inch    */ 
LL8              EQU 1B 30            /* set line length 8 lines per inch    */ 
E6L              EQU 1B 32            /* EPSON 6 LPI                         */  
E10              EQU 1B 50            /* EPSON 10 CPI                        */ 
E51              EQU 1B 43 33         /* 51 LINES PER PAGE                   */ 
RST              EQU 1B 40            /* Epson Reset                         */ 



/*****************************************************************************/ 
/* Control Codes                                                             */ 
/*****************************************************************************/ 
START_JOB = E51 E10 E6L               /* set 51 LInes per Page, 10CPI, 6LPI, */ 
END_JOB = RST                         /* Epson Reset                         */

Cautionary Notes:

All Epson emulations are not created equal. There are 3 Epson modes: 9-pin ESC/P, ESC/P and ESC/P2. Most vendors emulate ESC/P, although not necessarily completely. Write the PDF file with codes using ESC/P for greatest compatibility, testing each change. If the change does not take, obtain the correct code from the printer vendor's documentation.

The print server sends the LL6 or LL8 values based on the GUI setting after all of the START_JOB commands have been sent, overriding any LPI commands sent earlier in the PDT as follows:

1B 43 33 1B 32 (6LPI, PDT) 1B 50 1B 30 (8LPI, GUI Setting)

When you use the form size settings in Windows NT, Windows NT sends a form feed command when the configured form length (by counting the number of lines) is reached. If the printer is set for a different number of lines for a page size, the printer will form feed to its defined form size. An example may better illustrate this concept. If Windows NT is set for a form length of 8.5 inches at 6 Lines per inch and the printer is set for an 11 inch form, Windows NT sends a form feed after the 51st line. The printer performs the form feed to the top of the next 11 inch form, throwing off the print job entirely. Setting the paper source to Continuous Feed in the Windows NT Spooler printer properties does not override the form size that must be entered so the Windows NT setting and the Printer setting must match.

If, after matching form sizes, the print still does not seem to line up, there may be a difference in how Windows NT figures form length and the printer figures form length. To test this scenario, create a very long custom form in Windows NT and print using that form length. Observe where the printer is now performing the form feed to the next page and count the lines. Configure a form in Windows NT to match the number of lines that the printer is using, and the data will usually line up.

Dot-matrix printers may be set for Perforation Skip Over, which may also throw off lines per page calculations.

REFERENCES

www.epson.co.uk/support/manuals/select/escp.htm
www.oki.com
Microsoft SNA Server Print Service White Paper

Additional query words:

Keywords : sna3 sna4
Version : WINDOWS:3.0 (all SP),4.0,4.0 SP1,4.0 SP2,4.0 SP3,4.0 U.S. SP1
Platform : WINDOWS
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