ELM 329 - Page 77

Example Applications (continued)
Figure 12. A High Speed RS232 Interface (≤250 kbps)
ELM329
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+5V
10
11
12
13
14
15
16
17
18
19
20
21
22
+5V
329
2 (RxD)
RS232
Interface
(DB9F)
+5V
+5V
3 (TxD)
5 (SG)
1 (DCD)
4 (DTR)
6 (DSR)
7 (RTS)
8 (CTS)
4.7KΩ
10KΩ
10KΩ
1N4148
1N4148
0.1µF
4.7KΩ10KΩ
2N3906
2N3904
Figure 11. A Low Speed RS232 Interface (≤57.6 kbps)
+5V
10
11
12
13
14
15
16
17
18
19
20
21
22
+5V
329
2 (RxD)
RS232
Interface
(DB9F)
3 (TxD)
5 (SG)
1 (DCD)
4 (DTR)
6 (DSR)
7 (RTS)
8 (CTS)
0.1µF
+5V
0.1µF
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
0.47µF
U4
0.47µF
0.47µF