Unable to print to serial printer

Knowledge exchange related to the VPE Report Engine and PDF Library

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Unable to print to serial printer

Postby mrkelly » Mon Apr 17, 2006 9:14 pm

When printing labels to an Intermec 3400 printer on a serial port, we just get garbage. (There may also be some blank labels as well). Printing to the same printer in serial mode from outside of VPE is fine, and there is no problem printing to the same printer from within VPE if the printer is equipped with a parallel adapter.
Any suggestions would be appreciated.

Thanks,

Maurice
mrkelly
 
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Postby IDEAL Software Support » Tue Apr 18, 2006 6:11 pm

VPE does not access any printer ports itself. VPE uses the Windows GDI (Graphics Device Interface) to print on a very high system level, so this can only be caused by the printer driver (or maybe something wrong in the interaction between the driver and the rest of the system).

The fact that other applications like Word or Notepad might print correctly does not prove that the driver is error-free.

In contrast: We experienced that many printer driver manufacturers seem to test their drivers with some mainstream office application(s) and then they believe their drivers are working correctly. But debugging has proven that such drivers sometimes do not support some features as Microsoft has outlined in their API documentation and even more worse: they return wrong error codes or do not test for some parameters and things like that. VPE checks for such codes or uses parameters not used by the mainstream office applications and this is the reason why some faulty printer drivers produce "garbage" or do not print anything or - what we also experienced - they only print the first page. We already did invest about 3 man-years of work into VPE just to handle such problems by using workarounds. And thanks to god during the past years the printer drivers became more bug-free - at least regarding their main functionality (tray selection and paper dimension switching is sometimes still a problem).

Regards
Thorsten Radde
IDEAL Software GmbH
IDEAL Software Support
 
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