Epson FX-85 User Manual - Page 62

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printing, either by trial and error or by using the hex dumping capability of the FX, you can start overcoming them. Because each computer system deals with ASCII codes differently, it is impossible to provide solutions for all potential problems in one appendix. We can, however, point out generic problems and suggest ways to handle them. There are four common approaches. First, you may be able to buy an alternative printer interface card for your system. This is the best solution for 7-bit system problems. See your computer dealer for advice about this. The second approach is to use commercially available software that is specifically designed to overcome these coding problems. Consult your computer dealer or computer publications to see if a program for your computer system is available. The third approach consists of avoiding the software that is changing the codes. On most computers you can send each code directly to the printer. This bypasses the BASIC interpreter and avoids the interface. Unfortunately, this process is also different for each computer system. We'll give the procedure for a couple of systems here; if your system is not either of them, use the procedure as a model. Consult your computer's manual to determine if you can do the same on your system. A fourth approach is to change the printer driver program in your system. This requires a knowledge of machine language and of the way your computer works. If you don't have this knowledge, your computer dealer may be able to help you or suggest someone who can. We show a sample printer driver below (following the examples of POKEing codes). The idea is to pass the codes as issued by a BASIC program directly to the FX. POKEing codes The TRS-80 Model I version of the CHR$ function does not correctly pass on the values of 0, 10, 11, and 12. Zero is a particular problem as it is very important to the ESCape codes of the FX printers. 307

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printing, either by trial and error or by using the hex dumping capabil-
ity of the FX, you can start overcoming them.
Because each computer system deals with ASCII codes differently, it
is impossible to provide solutions for all potential problems in one
appendix. We can, however, point out generic problems and suggest
ways to handle them.
There are four common approaches. First, you may be able to buy
an alternative printer interface card for your system. This is the best
solution for 7-bit system problems. See your computer dealer for
advice about this.
The second approach is to use commercially available software that
is specifically designed to overcome these coding problems. Consult
your computer dealer or computer publications to see if a program for
your computer system is available.
The third approach consists of avoiding the software that is chang-
ing the codes. On most computers you can send each code directly to
the printer. This bypasses the BASIC interpreter and avoids the inter-
face.
Unfortunately, this process is also different for each computer sys-
tem. We’ll give the procedure for a couple of systems here; if your
system is not either of them, use the procedure as a model. Consult
your computer’s manual to determine if you can do the same on your
system.
A fourth approach is to change the printer driver program in your
system. This requires a knowledge of machine language and of the
way your computer works. If you don’t have this knowledge, your
computer dealer may be able to help you or suggest someone who
can.
We show a sample printer driver below (following the examples of
POKEing codes). The idea is to pass the codes as issued by a BASIC
program directly to the FX.
POKEing codes
The TRS-80 Model I version of the CHR$ function does not cor-
rectly pass on the values of
0, 10, 11,
and
12.
Zero is a particular
problem as it is very important to the ESCape codes of the FX printers.
307