Chapter 4, Sample application: ttl signals to eia-232, Digi one em hardware reference – Digi 90000278_B User Manual
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Digi One EM Hardware Reference
19
Chapter 4
S a m p l e A p p l i c a t i o n : T T L S i g n a l s t o
E I A - 2 3 2
The following figure is an example of how to convert the Digi
One EM signals to normal serial voltage levels.
0.
1uF
1
2
C6
0.
1uF
1
2
C4
0.
1uF
1
2
C3
0.
1uF
2
1
C5
+5
V
GN
D
11
10
9
8
7
6
5
4
3
2
1
DB9
P1
RS
-232 S
E
R
IA
L 9-
P
IN CO
NNE
CT
O
R
SH
IE
LD
SH
IE
LD
GN
D
GN
D
17
13
25
24
16
15
14
12
28
21
1
20
3
6
2
7
19
18
22
23
26
27
54
89
A
D
M211E
U1
RS
-232 LI
NE
RE
CV
R 5RX
4T
X
+5
V
GN
D
12
11
10
9
8
7
6
5
4
3
2
1
SO
C
KET
2
X6
DI
G
I O
N
E
E
M
CO
NNE
CT
O
R
P6
3
2
1
R
ESER
VED
H
EAD
ER
P5
GN
D
GN
D
GN
D
R
ESET
SW
IT
C
H
13
24
SW
1