Epson LX-80, Operating Manual

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Chapter 4
Printer Control Codes
The L X - 80 printer is easy to use , especially with commer cia l soft -
wa r e wh i c h h a s print control features . This chapter explain s some of
t h e basics of printer control and helps you understand how a compu-
t er com muni ca t es with the printer . This information should also
enab l e you to understand the term s used in the software or compu-
ter man u al .
If you are an a d va nced u se r or a pr o grammer , you m a y w a n t to turn
to Appendix B , w h e r e there i s a full s ummar y of all th e LX-80
commands.
When you type in a document u s ing a word proc ess ing program ,
you press keys w ith l e tt e r s or numb e rs on them and w h e n you send
the document to a print e r , it prints the corresponding l etters and
numbers onto th e p a p e r . The comput e r and the printer , h owever ,
do not use or understand letter s of the alphabet . They fun ction by
manipulating n umbe rs. Therefore , when you press the A key , for
example, the comput e r se nd s a number to its memor y. Wh en the
computer tel l s th e print e r to print that lett e r , it sends the n umber to
the printer, w hich mu s t th e n con v ert the number to a patt ern of pins
t h at will fire to print the dots th a t make up that letter .
T h e numbers that computers a nd printers use ar e in bin ary form ,
which means th a t the y us e onl y the digit s 0 and 1 . In thi s manual ,
however, we u se decim a l number s in our explanations bec a u se most
users are more fa miliar with th e s e numbers and bec a use m ost prog-
ramming l ang u a g es a nd a pplic a tions programs can u se decimal
numbers. The co mput e r sys tem or t he program take s car e of chang-
ing the decima l numb e r s to bin a ry form .