Table of Contents
Advertisement
94
Let's analyze the program. Line 20 defines the line spacing to
6/60 of an inch so that the characters that we print will touch top
to bottom. Lines 30 - 50 print 10 vertical line characters.
Then
line 70 sets uni-directional
printing
and the vertical lines are
printed again. Finally line 110 sends a form feed to advance the
paper to the top of a new page, and then uses the master reset to
restore the printer to the power on condition.
You can also set the printer to print in one direction for one
line only by using the (ESC) "(" command.
This command im-
mediately
moves the print head to the left margin and then
prints the remainder
of the line from left to right.
n The seven bit dilemma
Some computers
(not the IBM-PC fortunately!)
don't have the
capability to send eight bits on their parallel interface, but can
only send seven bits. This would make it impossible for these
computers
to use this printer's block graphics characters
and
special symbols if our engineers
hadn't thought
of a solution.
(All of these characters
have ASCII codes greater
than 127
which means that the eighth bit must be on to use them.) The
solution lies in the three control codes given in the following
table:
Advertisement
Table of Contents
