|
MOST SIGNIFICANT BITS |
|||||||||
|
LEAST SIGNIFICANT BITS |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
|
|
0 |
Null |
Data Link Escape |
Space |
0 |
@ |
P |
` |
p |
|
|
1 |
Start of Heading |
Device Control 1 |
! |
1 |
A |
Q |
a |
q |
|
|
2 |
Start of Text |
Device Control 2 |
“ |
2 |
B |
R |
b |
r |
|
|
3 |
End of Text |
Device Control 3 |
# |
3 |
C |
S |
c |
s |
|
|
4 |
End of Transmit |
Device Control 4 |
$ |
4 |
D |
T |
d |
t |
|
|
5 |
Enquiry |
Neg Acknowledge |
% |
5 |
E |
U |
e |
u |
|
|
6 |
Acknowledge |
Synchronous Idle |
& |
6 |
F |
V |
f |
v |
|
|
7 |
Bell |
End of Trans Block |
’ |
7 |
G |
W |
g |
w |
|
|
8 |
Backspace |
Cancel |
( |
8 |
H |
X |
h |
x |
|
|
9 |
Horizontal Tab |
End of Medium |
) |
9 |
I |
Y |
i |
y |
|
|
A |
Line Feed |
Substitute |
* |
: |
J |
Z |
j |
z |
|
|
B |
Vertical Tab |
Escape |
+ |
; |
K |
[ |
k |
{ |
|
|
C |
Form Feed |
File Separator |
, |
< |
L |
\ |
l |
| |
|
|
D |
Carriage Return |
Group Separator |
- |
= |
M |
] |
m |
} |
|
|
E |
Shift Out |
Record Separator |
. |
> |
N |
^ |
n |
~ |
|
|
F |
Shift In |
Unit Separator |
/ |
? |
O |
_ |
o |
Delete |
|
The American Standard Code for Information Interchange contains both printable and nonprintable characters, e.g., backspace or line feed. The devices that use ASCII data do not have to implement the entire character set. An LCD panel, for example, probably will not do anything if it receives the control character to ring a bell (0x7). If a device is an ASCII device, then it will only accept ASCII data, and numbers must be sent in their respective ASCII representations. For example, if you want to print a 9, then a printer must receive the value 0x39. Note that the most significant bit of an ASCII value is either zero or a parity bit, depending on how the programmer wants to use it.