Sending Commands to the Printer
This section describes how you can send commands directly to the
printer, allowing you to take full advantage of your printer’s
capabilities.
ASCII codes
Your computer communicates with your printer using a
standardized set of numbered codes called ASCII codes
(American Standard Code for Information Interchange). When
you press the letter A on the keyboard, it is translated into the
ASCII code for A, transmitted to a peripheral device such as your
computer screen or your printer, and then converted back into the
letter A.
There are ASCII codes for all the letters in the alphabet, both
uppercase and lowercase letters, and for the numbers 0 through 9.
The ASCII set of codes also includes most punctuation marks and
some codes that control printer functions.
In the Command Summary in Chapter 8, each ASCII code is
expressed three different ways: as an ASCII character, as a
decimal number, and as a hexadecimal number. Hexadecimal
numbering, or base 16, uses the numbers 0 through 9 plus the
letters A through F. For example, the uppercase letter K is
represented as the ASCII character K, the decimal number 75, and
the hexadecimal number 4B. All of these values are equivalent.
The numbering system you use depends on your software and
your preferences.
All letters, numbers, and punctuation marks are assigned decimal
numbers from 32 through 255. ASCII codes with decimal values of
less than 32 are called control codes because they control the
operation of your printer and other peripherals. These ASCII
characters do not usually have corresponding keys on the
keyboard and cannot be printed as characters by your printer.
(However, some software programs do use control key codes for
decimal values. See the Control Key chart in Chapter 8.)
4-8
Getting the Most from Your Printer
