ELM322
OBD
Interface
Notes: -
NPN transistor is a
2N3904 or similar
78L05
16
+5V
(Battery
Positive)
-
-
PNP transistors are
2N3906 or similar
0.47µF
750W
‘Power On’
LED
Diodes are 1N4148,
or 1N4001, etc.
5
(Vehicle
Ground)
10KW
+5V
4.7KW
100W
2
(Bus +)
+5V
0.01µF
+5V
1
8
7
6
5
27pF
3.58MHz
RS232
Interface
2
3
4
10KW
27pF
3 (RxD)
+5V
4.7KW
0.1µF
7 (SG)
4.7KW
47KW
10KW
2 (TxD)
100KW
Figure 4. Typical OBD to RS232 Interface
ELM322DSE
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