CHAPTER 7

DOWNLOAD CHARACTERS AND DOT GRAPHICS
Subjects covered in Chapter 7 include -
l Designing and printing your own characters
l User-designed graphics
Using the procedures outlined so far, all of the printer’s
standard functions can be utilized. There are two additional
user-defined functions available: designing and printing your
own characters, and designing and printing your own dot
graphics.
These two functions can be used to design and print any
symbol, or any graphic shape. This allows you to make your
own special symbols, or print a company logo. Some under-
standing of dot matrix technology will be useful.
DOT MATRIX PRINTING
Dot matrix printers are named because each character is
formed from a group of dots. The print head comprises nine
wires or pins stacked vertically. For any standard character,
up to seven of the pins are used at one time; for capital letters,
the top seven are used, fo,r standard height lower-case char-
acters, the center five pins, and for “descending” characters
(such as “p” or “g”), the bottom seven pins are used. The print
head moves across the paper and at any instant prints a vertical
series of dots; looking at Figure 7-l will reveal that the letter
“p” consists of five vertical columns of dots.
Any pin is tired by only one number, and any group of pins
is fired by a different number. One byte of data (a decimal
number from 0 to 25.3, can thus represent a unique combi-