Hex
|
Oct
|
Dec
|
ASCII
|
Msg
|
Hex
|
Oct
|
Dec
|
ASCII
|
Msg
|
00
|
000
|
0
|
NUL
|
20
|
040
|
32
|
SP
|
MLA0
| |
01
|
001
|
1
|
SOH
|
GTL
|
21
|
041
|
33
|
!
|
MLA1
|
02
|
002
|
2
|
STX
|
22
|
042
|
34
|
"
|
MLA2
| |
03
|
003
|
3
|
ETX
|
23
|
043
|
35
|
#
|
MLA3
| |
04
|
004
|
4
|
EOT
|
SDC
|
24
|
044
|
36
|
$
|
MLA4
|
05
|
005
|
5
|
ENQ
|
PPC
|
25
|
045
|
37
|
%
|
MLA5
|
06
|
006
|
6
|
ACK
|
26
|
046
|
38
|
&
|
MLA6
| |
07
|
007
|
7
|
BEL
|
27
|
047
|
39
|
'
|
MLA7
| |
08
|
010
|
8
|
BS
|
GET
|
28
|
050
|
40
|
(
|
MLA8
|
09
|
011
|
9
|
HT
|
TCT
|
29
|
051
|
41
|
)
|
MLA9
|
0A
|
012
|
10
|
LF
|
2A
|
052
|
42
|
*
|
MLA10
| |
0B
|
013
|
11
|
VT
|
2B
|
053
|
43
|
+
|
MLA11
| |
0C
|
014
|
12
|
FF
|
2C
|
054
|
44
|
,
|
MLA12
| |
0D
|
015
|
13
|
CR
|
2D
|
055
|
45
|
-
|
MLA13
| |
0E
|
016
|
14
|
SO
|
2E
|
056
|
46
|
.
|
MLA14
| |
0F
|
017
|
15
|
SI
|
2F
|
057
|
47
|
/
|
MLA15
| |
10
|
020
|
16
|
DLE
|
30
|
060
|
48
|
0
|
MLA16
| |
11
|
021
|
17
|
DC1
|
LLO
|
31
|
061
|
49
|
1
|
MLA17
|
12
|
022
|
18
|
DC2
|
32
|
062
|
50
|
2
|
MLA18
| |
13
|
023
|
19
|
DC3
|
33
|
063
|
51
|
3
|
MLA19
| |
14
|
024
|
20
|
DC4
|
DCL
|
34
|
064
|
52
|
4
|
MLA20
|
15
|
025
|
21
|
NAK
|
PPU
|
35
|
065
|
53
|
5
|
MLA21
|
16
|
026
|
22
|
SYN
|
36
|
066
|
54
|
6
|
MLA22
| |
17
|
027
|
23
|
ETB
|
37
|
067
|
55
|
7
|
MLA23
| |
18
|
030
|
24
|
CAN
|
SPE
|
38
|
070
|
56
|
8
|
MLA24
|
19
|
031
|
25
|
EM
|
SPD
|
39
|
071
|
57
|
9
|
MLA25
|
1A
|
032
|
26
|
SUB
|
3A
|
072
|
58
|
:
|
MLA26
| |
1B
|
033
|
27
|
ESC
|
3B
|
073
|
59
|
;
|
MLA27
| |
1C
|
034
|
28
|
FS
|
3C
|
074
|
60
|
<
|
MLA28
| |
1D
|
035
|
29
|
GS
|
3D
|
075
|
61
|
=
|
MLA29
| |
1E
|
036
|
30
|
RS
|
3E
|
076
|
62
|
>
|
MLA30
| |
1F
|
037
|
31
|
US
|
3F
|
077
|
63
|
?
|
UNL
| |
Message Definitions | ||||
DCL | Device Clear | MSA | My Secondary Address | |
GET | Group Execute Trigger | MTA | My Talk Address | |
GTL | Go To Local | PPC | Parallel Poll Configure | |
LLO | Local Lockout | PPD | Parallel Poll Disable | |
MLA | My Listen Address |
Hex
|
Oct
|
Dec
|
ASCII
|
Msg
|
Hex
|
Oct
|
Dec
|
ASCII
|
Msg
|
40
|
100
|
64
|
@
|
MTA0
|
60
|
140
|
96
|
`
|
MSA0,PPE
|
41
|
101
|
65
|
A
|
MTA1
|
61
|
141
|
97
|
a
|
MSA1,PPE
|
42
|
102
|
66
|
B
|
MTA2
|
62
|
142
|
98
|
b
|
MSA2,PPE
|
43
|
103
|
67
|
C
|
MTA3
|
63
|
143
|
99
|
c
|
MSA3,PPE
|
44
|
104
|
68
|
D
|
MTA4
|
64
|
144
|
100
|
d
|
MSA4,PPE
|
45
|
105
|
69
|
E
|
MTA5
|
65
|
145
|
101
|
e
|
MSA5,PPE
|
46
|
106
|
70
|
F
|
MTA6
|
66
|
146
|
102
|
f
|
MSA6,PPE
|
47
|
107
|
71
|
G
|
MTA7
|
67
|
147
|
103
|
g
|
MSA7,PPE
|
48
|
110
|
72
|
H
|
MTA8
|
68
|
150
|
104
|
h
|
MSA8,PPE
|
49
|
111
|
73
|
I
|
MTA9
|
69
|
151
|
105
|
i
|
MSA9,PPE
|
4A
|
112
|
74
|
J
|
MTA10
|
6A
|
152
|
106
|
j
|
MSA10,PPE
|
4B
|
113
|
75
|
K
|
MTA11
|
6B
|
153
|
107
|
k
|
MSA11,PPE
|
4C
|
114
|
76
|
L
|
MTA12
|
6C
|
154
|
108
|
l
|
MSA12,PPE
|
4D
|
115
|
77
|
M
|
MTA13
|
6D
|
155
|
109
|
m
|
MSA13,PPE
|
4E
|
116
|
78
|
N
|
MTA14
|
6E
|
156
|
110
|
n
|
MSA14,PPE
|
4F
|
117
|
79
|
O
|
MTA15
|
6F
|
157
|
111
|
o
|
MSA15,PPE
|
50
|
120
|
80
|
P
|
MTA16
|
70
|
160
|
112
|
p
|
MSA16,PPD
|
51
|
121
|
81
|
Q
|
MTA17
|
71
|
161
|
113
|
q
|
MSA17,PPD
|
52
|
122
|
82
|
R
|
MTA18
|
72
|
162
|
114
|
r
|
MSA18,PPD
|
53
|
123
|
83
|
S
|
MTA19
|
73
|
163
|
115
|
s
|
MSA19,PPD
|
54
|
124
|
84
|
T
|
MTA20
|
74
|
164
|
116
|
t
|
MSA20,PPD
|
55
|
125
|
85
|
U
|
MTA21
|
75
|
165
|
117
|
u
|
MSA21,PPD
|
56
|
126
|
86
|
V
|
MTA22
|
76
|
166
|
118
|
v
|
MSA22,PPD
|
57
|
127
|
87
|
W
|
MTA23
|
77
|
167
|
119
|
w
|
MSA23,PPD
|
58
|
130
|
88
|
X
|
MTA24
|
78
|
170
|
120
|
x
|
MSA24,PPD
|
59
|
131
|
89
|
Y
|
MTA25
|
79
|
171
|
121
|
y
|
MSA25,PPD
|
5A
|
132
|
90
|
Z
|
MTA26
|
7A
|
172
|
122
|
z
|
MSA26,PPD
|
5B
|
133
|
91
|
MTA27
|
7B
|
173
|
123
|
{
|
MSA27,PPD
| |
5C
|
134
|
92
|
\
|
MTA28
|
7C
|
174
|
124
|
|
|
MSA28,PPD
|
5D
|
135
|
93
|
MTA29
|
7D
|
175
|
125
|
}
|
MSA29,PPD
| |
5E
|
136
|
94
|
^
|
MTA30
|
7E
|
176
|
126
|
~
|
MSA30,PPD
|
5F
|
137
|
95
|
_
|
UNT
|
7F
|
177
|
127
|
DEL
| |
Message Definitions | ||||
PPE | Parallel Poll Enable | SPE | Serial Poll Enable | |
PPU | Parallel Poll Unconfigure | TCT | Take Control | |
SDC | Selected Device Clear | UNL | Unlisten | |
SPD | Serial Poll Disable | UNT | Untalk |
For example, the ASCII "@" character (hex 40) represents the message "MTA0", which assigns the device at primary address zero as the Talker. As another example, the ASCII "?" character (hex 3F) represents the message "UNL", which instructs all devices that had previously been assigned as Listeners to unlisten (that is, stop listening).
The Multiline Interface Message Table is very useful, if you are using the board-level GPIB function ibcmd. As a Controller, you would use the ibcmd function to send command messages. For example, if you were using the Interactive Control (IBIC) to assign the Controller (PAD 0) as the Talker and an instrument (PAD 5) as the Listener, you would use ibcmd "?@%" to instruct all devices to stop listening (?, UNL), the Controller to talk (@, MTA0), and the instrument to listen (%, MLA5).
The Controller would then send data to the instrument with the ibwrt function. (Note: Calling ibwrt will cause the ATN line to deassert, so that the data lines on the bus are used to send data messages, instead of command messages.) To continue with the previous example, you could use ibwrt "hello" to send the data message hello to the instrument. (Of course, the message you send should make sense to the instrument.)