TM 11-5815-602-10
EE161-DM-OPl-010/E154UGC74
TO 31W4-2UGC74-1
ASCII is the standard code, using a coded character set consisting of 7-bit coded characters (8
bits including parity check), used for information interchange among data processing systems,
data communication systems, and associated equipment. The ASCII set consists of control
characters and graphic characters.
Control Character: A functional character, distinct from a graphic character, which is in-
tended to assist information exchange by controlling or modifying the function of
machines or systems. Control characters are intended to be translated by machines
rather than human beings; therefore, they are normally non-printing characters.
Graphic Character: A character intended to be printed or otherwise shown in a legible
form.
128-Symbol Set. The complete standard set of 128 printing symbols is given in table E-1.
q
There are actually only 127 printing symbols since the space is non-printing.
96-Symbol Subset. The standard 96 symbol subset of printing symbols includes the symbols
q
contained in columns 2 through 7 of table E-1 (95 printing symbols plus space). The
heart symbol may be printed instead of the symbol for the control characters shown in
columns O and 1 in table E-1.
64-Symbol Subset. The standard 64 symbol subset of printing symbols for page/printer ap-
q
plications is given in table E-2. The heart symbol
may be printed instead of the sym-
bol for the control characters shown in columns O and 1 in table E-1. The 64-Symbol set
is used by the AN/UGC-74A(V)3.
E.3. ASCII CHARACTER REPRESENTATION
a. The standard 7-bit character representation, with b7, the high-order bit, and b1, the low-order
bit, is shown below. (Order of bit transmission is specified in c below.)
Example: The bit representation for the character "K" (see table E-1) is:
b7 b6 b5 b4 b3 b2 b1
1001011
The code table position for the character "K" may also be represented by the notation
"column 4, row 11" or alternatively as "4/11".
The decimal equivalent of the binary number formed by bits b7, b6, and b5, collectively,
forms the column number, and the decimal equivalent of the binary number formed by
bits b4, b3, b2, and b1, collectively, forms the row number.
b. For military purposes, a parity bit, b8 is always added to the standard character. This per-
mits detection of bit groupings which contain single errors.
c. In serial-by-bit transmission, the coded character will be transmitted low order first; i.e.,
the bits will appear on-line in the order b1, b2, b3, b4, b5, b6, b7, b8, (parity).
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