Appendix A



ASCII Code



ASCII (American Standard Code for Information Interchange), pronounced Ask-Key, is like Morse Code for the computer. There is no particular reason why number 65 should stand for A, but someone had to decide what stood for what. If you really get into it, you'll find very good reasons for certain relationships (the difference between capital A and lower case a, 65 versus 97, represents just one bit in a binary byte that is a 0 rather than a 1); this is why you may detect some patterns even if you are not a programmer.
        Within the ASCII code, the numbers 32-126 produce printed characters, either on a screen or a printer. The numbers 0-31 and 127 are controls that cause some other activity on the part of either the printer or computer.
        The original ASCII Code included some controls for early mainframe computers, which are not used for your micro (some of the codes are used for something else, others are just ignored), so the symbols for some of the non-printing characters may not be familiar to you.
        The numbers from 128 to 255 are employed differently by different computers and printers. Check your manual, for example, to see if your printer uses 128-255 to repeat 0-127, or to print italics, or to hold an alternate character set, or graphics. Some can be programmed with characters you design.
        The chart below shows the decimal value for codes 0-127, and the printed character, when there is one. For the non-printing controls, we've shown the ASCII abbreviation ("symbol" or "mnemonic") and its definition, as well as the keystroke(s) that will produce the code (on most computers, but not all). Again, these may not all be meaningful to you, but the next Appendix will give you a better idea of how to use them with your Epson printer.
        The decimal number, used with the BASIC language command CHR$-as PRINT CHR$(65)-will produce the character or action in question. (If you happen to be using BASIC and want to know what CHR$ number goes with a character, this will produce the answer: PRINT CODE "A".

NOTE: This is the standard ASCII character set, used by all Epson printers and most computers. Your Atari's character set is slightly different-see the manual. With the PIC, a HomeWriter-10 or LX90 will produce the computer's character set rather than this one. With another interface, in transparent mode, you'll get these characters-which means that what you see on the screen will be different from what the printer will print for a particular CHR$ number.


DECIMAL SYMBOL KEYBOARD MEANING
0   
NUL
 CTRL @ or
CTRL SHIFT P
 Null
1   
SOH
 CTRL A
 Start of Heading
2   
STX
 CTRL B
 Start of Text
3   
ETX
 CTRL C
 End of Text, BREAK
4   
EOT
 CTRL D
 End of Transmission
5   
ENQ
 CTRL E
 Enquiry
6   
ACK
 CTRL F
 Acknowledge
7   
BEL
 CTRL G
 Sound bell or buzzer
8   
BS
 CTRL H
 Backspace
9   
HT
 CTRL I
 Horizontal tab
10   
LF
 CTRL J
 Line feed
11   
VT
 CTRL K
 Vertical tab
12   
FF
 CTRL L
 Form feed
13   
CR
 CTRL M
 Carriage return
14   
SO
 CTRL N
 Shift Out
15   
SI
 CTRL O
 Shift In
16   
DLE
 CTRL P
 Data Link Escape
17   
DC1
 CTRL Q
 Device Control 1, Reader
 On
18   
DC2
 CTRL R Device Control 2, Punch
 On
19   
DC3
 CTRL S
 Device Control 3, Reader
 Off
20   
DC4
 CTRL T
 Device Control 4, Punch
 Off
21   
NAK
 CTRL U
 Negative Acknowledge
22   
SYN
 CTRL V
 Synchronous Idle
23   
ETB
 CTRL W
 End  of  Transmission
 Block
24   
CAN
 CTRL X
 Cancel
25   
EM
 CTRL Y
 End of Medium
26   
SUB
 CTRL Z
 Substitute
27   
ESC
 CTRL SHIFT K
 Escape
28   
FS
 CTRL SHIFT L File Separator
29   
GS
 CTRL SHIFT M Group Separator
30   
RS
 CTRL SHIFT N Record Separator
31   
SP
 Space bar
 Space, blank
127   
DEL
 DELETE
 Delete

CHR$ CHAR CHR$ CHAR CHR$ CHAR
33
 !
 65
 A
 97
 a
34
 "
 66
 B
 98
 b
35
 #
 67
 C
 99
 c
36
 $
 68
 D
 100
 d
37
 %
 69
 E
 101
 e
38
 &
 70
 F
 102
 f
39
 '
 71
 G
 103
 g
40
 (
 72
 H
 104
 h
41
 )
 73
 I
 105
 i
42
 *
 74
 J
 106
 j
43
 +
 75
 K
 107
 k
44
 ,
 76
 L
 108
 l
45
 -
 77
 M
 109
 m
46
 .
 78
 N
 110
 n
47
 /
 79
 O
 111
 o
48
 0
 80
 P
 112
 p
49
 1
 81
 Q
 113
 q
50
 2
 82
 R
 114
 r
51
 3
 83
 S
 115
 s
52
 4
 84
 T
 116
 t
53
 5
 85
 U
 117
 u
54
 6
 86
 V
 118
 v
55
 7
 87
 W
 119
 w
56
 8
 88
 X
 120
 x
57
 9
 89
 Y
 121
 y
58
 :
 90
 Z
 122
 z
59
 ;
 91
 [
 123
 {
60
 <
 92
 \
 124
 |
61
 =
 93
 ]
 125
 }
62
 >
 94
 ^
 126
 ~
63
 ?
 95
 _
 127
64
 @
 96
 `

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