Re: HP42S Input Project Status Report Message #4 Posted by Andrés C. Rodríguez (Argentina) on 16 Sept 2001, 8:47 p.m., in response to message #3 by Tony Duell
Tony:
Keep in mind that, at least in the Windows environment, it is not easy to send arbitrary bytes to the parallel port. The printer drivers take care of any control codes (below 20 hex), even the "generic text" driver masks (filters) any non-printable characters.
I found this out last year, trying to drive a thermal printer from Windows. The thermal ticket printer has a lot of functions like graphics, barcodes, etc, which are activated sending special escape sequences. Since a Windows driver was not available, I was not able to access such functions. (I found a way to "hack" it, but that is another story)
So, our options are:
a1) Restrict the codes to printable characters... this may need clever use of the possible codes (*), or
a2) Same as a1) but using a EPROM to translate some codes into others...
b) Write a Windows printer driver
c) Use a serial port (even without "serial" hardware!)
d) Avoid the Windows environment
The option a1) marked with an asterisk seems the most convenient from my point of view...
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