ASCII

Null
NUL - control character (in a strict sense, an idle and not a control character)
⎕ U+2395
hex:00 bin:000.0000 oct:000 dec:0
C represents with \0
In some media, the NUL character meant that no holes are punched, or no tabs broken, and interpreted as an “idle” as something to ignore

Start of Heading
SOH - transmission control
⌈ U+2308
hex:01 bin:000.0001 oct:001 dec:1

Start of Text
STX - transmission control
⊥ U+22A5
hex:02 bin:000.0010 oct:002 dec:2

End of Text
ETX - transmission control
⌋ U+230B
hex:03 bin:000.0011 oct:003 dec:3

End of Transmission
EOT - transmission control
⌁ U+2301
hex:03 bin:000.0011 oct:003 dec:3
hex:04 bin:000.0100 oct:004 dec:4

Enquiry
ENQ - transmission control
⊠ U+22A0
hex:05 bin:000.0101 oct:005 dec:5

Acknowledgement
ACK - transmission control
✓ U+2713
hex:06 bin:000.0110 oct:006 dec:6

Bell
BEL - control character
⍾ U+237E
hex:07 bin:000.0111 oct:007 dec:7
C represents with \a (for alert)

Backspace
BS - format effector
↶ U+21B6
hex:08 bin:000.1000 oct:010 dec:8
C represents with \b

Horizontal Tab
HT - format effector
⪫ U+2AAB
hex:09 bin:000.1001 oct:011 dec:9
C represents with \t

Line Feed
LF - format effector
≡ U+2261
hex:0A bin:000.1010 oct:012 dec:10
C represents with \n
Many operating systems use LF as the end-of-line
CP/M uses CRLF, and operating systems like DOS, OS/2, and Windows which where influenced by CP/M still use CRLF
Fun fact: ASCII-1967 (USAS X3.4-1967) specified CRLF or LFCR to be used as a newline
Fun fact: ASCII-1968 (USAS X3.4-1968) allowed LF alone to be used as a newline, by allowing for an “optional implicit CR”

Vertical Tab
VT - format effector
⩛ U+2A5B
hex:0B bin:000.1011 oct:013 dec:11
C represents with \v

Form Feed
FF - format effector
↡ U+21A1
hex:0C bin:000.1100 oct:014 dec:12
C represents with \f

Carriage Return
CR - format effector
⪪ U+2AAA
hex:0D bin:000.1101 oct:015 dec:13
C represents with \r
Apple’s AppleDOS, ProDOS, GS/OS, Macintosh (until MacOS 9) used CR as end-of-line
Fun fact: ASCII-1968 (USAS X3.4-1968) allowed LF alone to be used as a newline, by allowing for an “optional implicit CR”
(Apple didn't get the memo until OS X.)

Shift Out
SO - control character
⊗ U+2297
hex:0E bin:000.1110 oct:016 dec:14

Shift In
SI - control character
⊙ U+2299
hex:0F bin:000.1111 oct:017 dec:15

Data Link Escape
DLE - transmission control
⊟ U+229F
hex:10 bin:001.0000 oct:020 dec:16

Device Control 1
DC1 - device control
◷ U+25F7
hex:11 bin:001.0001 oct:021 dec:17
often used for XON “transmission on”

Device Control 2
DC2 - device control
◶ U+25F6
hex:12 bin:001.0010 oct:022 dec:18

Device Control 3
DC3 - device control
◵ U+25F5
hex:13 bin:001.0011 oct:023 dec:19
often used for XOFF “transmission off”

Device Control 4
DC4 - device control
◴ U+25F4
hex:14 bin:001.0100 oct:024 dec:20

Negative Acknowledgement
NAK - transmission control
⍻ U+237B
hex:15 bin:001.0101 oct:025 dec:21

Synchronous Idle
SYN - transmission control
⎍ U+238D
hex:16 bin:001.0110 oct:026 dec:22

End of Transmission Block
ETB - transmission control
⊣ U+22A3
hex:17 bin:001.0111 oct:027 dec:23

Cancel
CAN - application defined character
⧖ U+29D6
hex:18 bin:001.1000 oct:030 dec:24

End of Medium
EM - control character
⍿ U+237F
hex:19 bin:001.1001 oct:031 dec:25

Substitute
SUB - control character
␦ U+2426
hex:1A bin:001.1010 oct:032 dec:26

Escape
ESC - application defined character; control sequence introducer (ISO 2022)
⊖ U+2296
hex:1B bin:001.1011 oct:033 dec:27
Some C compilers have a non-standard extension representing with \e

File Separator
FS - information separator (application defined)
◰ U+25F0
hex:1C bin:001.1100 oct:034 dec:28

Group Separator
GS - information separator (application defined)
◱ U+25F1
hex:1D bin:001.1101 oct:035 dec:29

Record Separator
RS - information separator (application defined)
◲ U+25F2
hex:1E bin:001.1110 oct:036 dec:30

Unit Separator
US - information separator (application defined)
◳ U+25F3
hex:1F bin:001.1111 oct:037 dec:31

Space
SP - non-printing graphic character; format effector
△ U+25B3
hex:20 bin:010.0000 oct:040 dec:32

!
bang
hex:21 bin:010.0001 oct:041 dec:33
Fun fact: ASCII-1967 (USAS X3.4-1967) this character could be “stylized” as | logical OR (vertical bar), which is why 7C was a ¦ broken bar
Fun fact: ASCII-1977 (ANSI X3.4-1977) put the kibosh on “stylized” | logical OR

"
quote
hex:22 bin:010.0010 oct:042 dec:34

#
crunch, hash, pound, octothorpe
hex:23 bin:010.0011 oct:043 dec:35
Fun fact: ASCII-1967 (USAS X3.4-1967) this character could be “stylized” as £ pound sterling
Fun fact: ASCII-1977 (ANSI X3.4-1977) put the kibosh on “stylized” as £ pound sterling
ISO 646-1973 designated this as # number sign or £ pound sterling

$
cash, dollar
hex:24 bin:010.0100 oct:044 dec:36
ISO 646-1973 designated this as ¤ currency sign or $ dollar sign

%
percent
hex:25 bin:010.0101 oct:045 dec:37

&
and, ampersand
hex:26 bin:010.0110 oct:046 dec:38

'
tick
hex:27 bin:010.0111 oct:047 dec:39

(
paren
hex:28 bin:010.1000 oct:050 dec:40

)
unparen
hex:29 bin:010.1001 oct:051 dec:41

*
splat, star - numeric symbol
hex:2A bin:010.1010 oct:052 dec:42
Fun fact: 2A..39 are intentionally grouped as numeric related symbols and digits, with binary coded decimal (BCD) usage in mind

+
plus - numeric symbol
hex:2B bin:010.1011 oct:053 dec:43

,
comma - numeric symbol
hex:2C bin:010.1100 oct:054 dec:44

-
minus, dash, hyphen - numeric symbol
hex:2D bin:010.1101 oct:055 dec:45

.
dot - numeric symbol
hex:2E bin:010.1110 oct:056 dec:46

/
slash - numeric symbol
hex:2F bin:010.1111 oct:057 dec:47

0
zero - numeric digit
hex:30 bin:011.0000 oct:060 dec:48

1
one - numeric digit
hex:31 bin:011.0001 oct:061 dec:49

2
two - numeric digit
hex:32 bin:011.0010 oct:062 dec:50

3
three - numeric digit
hex:33 bin:011.0011 oct:063 dec:51

4
four - numeric digit
hex:34 bin:011.0100 oct:064 dec:52

5
five - numeric digit
hex:35 bin:011.0101 oct:065 dec:53

6
six - numeric digit
hex:36 bin:011.0110 oct:066 dec:54

7
seven - numeric digit
hex:37 bin:011.0111 oct:067 dec:55

8
eight - numeric digit
hex:38 bin:011.1000 oct:070 dec:56

9
nine - numeric digit
hex:39 bin:011.1001 oct:071 dec:57

:
colon
hex:3A bin:011.1010 oct:072 dec:58
ISO R 646-1967 designated this as optionally the symbol for 10 in the British pound sterling monetary system (dropped in ISO 646-1973, since Britian went decimal in 1971)
There is no Unicode symbol for "10". Unicode U+2491 ⒑ "Number Ten Full Stop" comes close.

;
semicolon, semi
hex:3B bin:011.1011 oct:073 dec:59
ISO R 646-1967 designated this as optionally the symbol for 11 in the British pound sterling monetary system (dropped in ISO 646-1973, since Britian went decimal in 1971)
There is no Unicode symbol for "11". Unicode U+2492 ⒒ "Number Eleven Full Stop" comes close.

<
less-than, angle
hex:3C bin:011.1100 oct:074 dec:60

=
equal
hex:3D bin:011.1101 oct:075 dec:61

>
greater-than, unangle
hex:3E bin:011.1110 oct:076 dec:62

?
query, question-mark
hex:3F bin:011.1111 oct:077 dec:63

@
at, commercial at
hex:40 bin:100.0000 oct:100 dec:64
ISO 646-1973 designated this as a national use character

A
Capital A
hex:41 bin:100.0001 oct:101 dec:65

B
Capital B
hex:42 bin:100.0010 oct:102 dec:66

C
Capital C
hex:43 bin:100.0011 oct:103 dec:67

D
Capital D
hex:44 bin:100.0100 oct:104 dec:68

E
Capital E
hex:45 bin:100.0101 oct:105 dec:69

F
Capital F
hex:46 bin:100.0110 oct:106 dec:70

G
Capital G
hex:47 bin:100.0111 oct:107 dec:71

H
Capital H
hex:48 bin:100.1000 oct:110 dec:72

I
Capital I
hex:49 bin:100.1001 oct:111 dec:73

J
Capital J
hex:4A bin:100.1010 oct:112 dec:74

K
Capital K
hex:4B bin:100.1011 oct:113 dec:75

L
Capital L
hex:4C bin:100.1100 oct:114 dec:76

M
Capital M
hex:4D bin:100.1101 oct:115 dec:77

N
Capital N
hex:4E bin:100.1110 oct:116 dec:78

O
Capital O
hex:4F bin:100.1111 oct:117 dec:79

P
Capital P
hex:50 bin:101.0000 oct:120 dec:80

Q
Capital Q
hex:51 bin:101.0001 oct:121 dec:81

R
Capital R
hex:52 bin:101.0010 oct:122 dec:82

S
Capital S
hex:53 bin:101.0011 oct:123 dec:83

T
Capital T
hex:54 bin:101.0100 oct:124 dec:84

U
Capital U
hex:55 bin:101.0101 oct:125 dec:85

V
Capital V
hex:56 bin:101.0110 oct:126 dec:86

W
Capital W
hex:57 bin:101.0111 oct:127 dec:87

X
Capital X
hex:58 bin:101.1000 oct:130 dec:88

Y
Capital Y
hex:59 bin:101.1001 oct:131 dec:89

Z
Capital Z
hex:5A bin:101.1010 oct:132 dec:90

[
square, left square bracket
hex:5B bin:101.1011 oct:133 dec:91
ISO 646-1973 designated this as a national use character

\
backslash, whack
hex:5C bin:101.1100 oct:134 dec:92
Fun fact: backslash almost did not make it into ASCII, as it had no prior usage in data, computing, or printing. It won over the hearts and minds of the committee when it could be combined with slash to form /\ as logical AND as well for \/ as logical OR in a programming language yet to be devised. C uses && for logical AND, and || for logical OR. Oh well.
ISO 646-1973 designated this as a national use character

]
unsquare, right square bracket
hex:5D bin:101.1101 oct:135 dec:93
ISO 646-1973 designated this as a national use character

^
circumflex, caret
hex:5E bin:101.1110 oct:136 dec:94
Fun fact: ASCII-1963 (ASA X3.4-1963) this character is ↑
Fun fact: ASCII-1967 (USAS X3.4-1967) this character could be “stylized” ¬ logical NOT
Fun fact: ASCII-1977 (ANSI X3.4-1977) put the kibosh on “stylized” ¬ logical NOT
ISO 646-1973 designated this as an extended national use character

_
underbar, underscore
hex:5F bin:101.1111 oct:137 dec:95
Fun fact: ASCII-1963 (ASA X3.4-1963) this character is ←

`
grave, grave accent, backtick, birk
hex:60 bin:110.0000 oct:140 dec:96
ISO 646-1973 designated this as an extended national use character

a
minuscule a
hex:61 bin:110.0001 oct:141 dec:97

b
minuscule b
hex:62 bin:110.0010 oct:142 dec:98

c
minuscule c
hex:63 bin:110.0011 oct:143 dec:99

d
minuscule d
hex:64 bin:110.0100 oct:144 dec:100

e
minuscule e
hex:65 bin:110.0101 oct:145 dec:101

f
minuscule f
hex:66 bin:110.0110 oct:146 dec:102

g
minuscule g
hex:67 bin:110.0111 oct:147 dec:103

h
minuscule h
hex:68 bin:110.1000 oct:150 dec:104

i
minuscule i
hex:69 bin:110.1001 oct:151 dec:105

j
minuscule j
hex:6A bin:110.1010 oct:152 dec:106

k
minuscule k
hex:6B bin:110.1011 oct:153 dec:107

l
minuscule l
hex:6C bin:110.1100 oct:154 dec:108

m
minuscule m
hex:6D bin:110.1101 oct:155 dec:109

n
minuscule n
hex:6E bin:110.1110 oct:156 dec:110

o
minuscule o
hex:6F bin:110.1111 oct:157 dec:111

p
minuscule p
hex:70 bin:111.0000 oct:160 dec:112

q
minuscule q
hex:71 bin:111.0001 oct:161 dec:113

r
minuscule r
hex:72 bin:111.0010 oct:162 dec:114

s
minuscule s
hex:73 bin:111.0011 oct:163 dec:115

t
minuscule t
hex:74 bin:111.0100 oct:164 dec:116

u
minuscule u
hex:75 bin:111.0101 oct:165 dec:117

v
minuscule v
hex:76 bin:111.0110 oct:166 dec:118

w
minuscule w
hex:77 bin:111.0111 oct:167 dec:119

x
minuscule x
hex:78 bin:111.1000 oct:170 dec:120

y
minuscule y
hex:79 bin:111.1001 oct:171 dec:121

z
minuscule z
hex:7A bin:111.1010 oct:172 dec:122

{
brace, curly
hex:7B bin:111.1011 oct:173 dec:123
ISO 646-1973 designated this as a national use character

|
bar, vertical bar
hex:7C bin:111.1100 oct:174 dec:124
Fun fact: ASCII-1967 (USAS X3.4-1967) this character is ¦ broken bar, which was a concession to supporting 6-bit character set, and to avoid colliding with | logical OR (an alternative “stylization” of the ! exclamation mark character)
Fun fact: ASCII-1977 (ANSI X3.4-1977) changed this character to the | vertical bar we all know and love
IBM PC shipped in 1981, and the character set had a broken bar at 7C, as part of the OEM 437 code page
ISO 646-1973 designated this as a national use character

}
unbrace, uncurly
hex:7D bin:111.1101 oct:175 dec:125
ISO 646-1973 designated this as a national use character

~
tilde, twiddle, squiggle, wiggle, squiggly
hex:7E bin:111.1110 oct:176 dec:126
Fun fact: ASCII-1967 (USAS X3.4-1967) this character could be “stylized” as ˜ upper tilde when used as diacritic
Fun fact: ASCII-1967 (USAS X3.4-1967) this character could be “stylized” as ‾ overline when used as punctuation (but didn't actually look like an overline)
Fun fact: ASCII-1967 (USAS X3.4-1967) this character could be “stylized” as ~ midline tilde when used as punctuation
Fun fact: ASCII-1977 (ANSI X3.4-1977) put the kibosh on all the variations, and fixed the character to be simply ˜ tilde
Fun fact: tilde was included in ASCII as its own character because of 19th century typewriters that supported Spanish or Portuguese. Those typewriters would have a tilde "dead key" that did not advance the carriage, so the character would overstrike the same position.
ISO 646-1973 designated this as an extended national use character, and is otherwise ‾ overline (not tilde)

Delete
DEL - control character (in a strict sense, an idle and not a control character)
␥ U+2425
hex:7F bin:111.1111 oct:177 dec:127
In some media, the DEL character meant that all the holes are punched, or all tabs broken, and interpreted as an “idle” as something to ignore