20 Delta User’s Manual
10) Since hex needs 16 digits, it uses the numbers 0 through 9 and
then it uses the letters A through F for digits. The ASCII code for
the letter “A” is 41 in HEX.
Of course, most of the time we don’t even need to think about
this code system. Our computers are smart enough to know that
when we press the “A” key on our keyboard we want to print the
letter “A”. The computer takes care of all the rest.
But there are a number of ASCII codes that don’t have keys on
the keyboard. The most important of these codes are the codes
that have ASCII values below 32. These codes control many of
Delta’s functions. Even though there aren’t keys for these codes,
most keyboards can send these codes. It’s done by holding down
the “control” key (many times marked CTRL) and simultaneously -
pressing a letter key. The particular letter key that is pressed deter-
mines what code is sent. Control and A sends ASCII code 1, con-
trol and B sends ASCII code 2, and so on. Because of the way they
are created, these codes are often referred to as “control-A” etc.
So there are four common ways of referring to the same set of
codes: the character or name of the code, the decimal ASCII
value, the hexadecimal ASCII value, and the “control-” value.
For example, the code that causes Delta to advance the paper
one line is ASCII 10 (decimal). This code is commonly referred to
by all the following names:
line feed - its name
(LF) - the abbreviation of its name
ASCII 10 - its decimal value
ASCII OAH - its hex value (the H signifies hex)
CHR$(lO) - the way it’s used in BASIC
control-J - the way you send it from a keyboard.
There’s a chart in Appendix M that shows these side-by-side so
that you can convert back and forth.
The reason that we are telling you all this about ASCII codes
is that people are not very consistent about how they describe
ASCII codes. We are going to help you use Delta with commercial
software, but we don’t know what its documentation is going to
call the various codes. So if you know all the different things that
the codes might be called it will be easier to figure out what it is
trying to tell you.
Now, armed with the knowledge of what to look for, you can
delve into the manuals of your commercial software and dig out
the secrets of how to send “control codes” to your printer. When