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Note that we didn’t have to re-enter the download characters,
since they were already sent to the printer with the first pro-
gram. They will stay with the printer until you download new
characters to replace them or turn the printer off. Even the
(ESC) “a” command, which initializes the printer, does not
destroy the contents of download RAM.
DEFINING PROPORTIONAL CHARACTERS
Except for the actual width, defining characters for propor-
tinal printing is exactly the same as defining normal width
download characters. Characters can range from 5 to 11 dots
wide. This means that characters can be as narrow as one-half
the normal width.
Besides being able to specify the actual width of the
character, this printer allows you to specify the position in the
standard grid where the character will print. You must specify
the dot column in which the printed character starts and the dot
column in which the character ends. Why, you may ask, would
you want to define a character this way instead of merely defin-
ing the overall width of the character? Because this printer’s pro-
portional character definitions can also be used to print normal
width characters, which are eleven dot columns wide. And by
centering even the narrow characters in the complete grid they
will look good even when you aren’t printing them proportional-
ly.
. The command format for proportional character definition is
exactly the same as you have learned; the only difference is the
attribute byte, m0. As you know,the first bit of m0 is used to
specify whether the character is descender or not. The next
three bits are used to specify the starting print column (accep-
table values are 0 to 7). The last four bits specify the ending
print column (acceptable values are 4 to 11). The minimum
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