The “Baudot” Code

This table presents a programmer’s quick reference to the “Baudot” character set.

IMPORTANT NOTE: The code presented here is with reference to usage in the computer industry. The original, true, baudot code differs from that presented below. The following table presents CCITT Alphabet No 2 which was developed from Murray’s code which was in turn developed from Baudot’s code. Baudot’s code was replaced by Murray’s code in 1901.
And ITA2 replaced both by the early 1930’s, so virtually all “teletype” equipment made in the U.S. uses ITA2 or the U.S. national version of the code.

The ‘baudot’ code has been used extensively in telegraph systems. It is a five bit code invented by the Frenchman Emile Baudot in 1870. Using five bits allowed 32 different characters. To accomodate all the letters of the alphabet and numerals, two of the 32 combinations were used to select alternate character sets. The figures column is valid after a figures shift character has been received. It remains in effect until a letters shift is received, after which the letters column should be referred to (and vice-versa).

Two ‘Baudot codes’ are in common useage. The first as used in America. The second, used in Europe, is also termed the CCITT Alphabet No. 2. In each, the ‘letters’ are identical, but the ‘figures’ differ.

The five-bit words are bracketed by a start bit (space) and a stop bit (mark). Idling is shown by the ‘marking’ state. Words are transmitted LSB first.

Binary
Decimal
Hex
Octal
Letter
U.S.
Figures
CCITT No.2
Figures
00000
0
0
0
N/A
N/A
N/A
00001
1
1
1
E
3
3
00010
2
2
2
LF
LF
LF
00011
3
3
3
A
00100
4
4
4
Space
Space
Space
00101
5
5
5
S
BELL
00110
6
6
6
I
8
8
00111
7
7
7
U
7
7
01000
8
8
10
CR
CR
CR
01001
9
9
11
D
$
WRU
01010
10
A
12
R
4
4
01011
11
B
13
J
Bell
01100
12
C
14
N
,
,
01101
13
D
15
F
!
!
01110
14
E
16
C
:
:
01111
15
F
17
K
(
(
10000
16
10
20
T
5
5
10001
17
11
21
Z
+
10010
18
12
22
L
)
)
10011
19
13
23
W
2
2
10100
20
14
24
H
#
£
10101
21
15
25
Y
6
6
10110
22
16
26
P
0
0
10111
23
17
27
Q
1
1
11000
24
18
30
O
9
9
11001
25
19
31
B
?
?
11010
26
1A
32
G
&
&
11011
27
1B
33
Figures Shift
Figures Shift
Figures Shift
11100
28
1C
34
M
.
.
11101
29
1D
35
X
/
/
11110
30
1E
36
V
;
=
11111
31
1F
37
Letters Shift
Letters Shift
Letters Shift