Westermo MA-45 - Manual (Page 27)

Block diagram
V.11/RS-422
RS-485
V.24/RS-232
3
4
A
B
TD LED TD LED
2
TD
CTS
LED
S3:4
F1
0V
+5V
1
2
A’
B’
5
0V
RTS
CTS
RD
RD
LED
4
5
3
B
B
0V SG
S2:6
Shield
DSR
6
+5V
7
S3:2
S3:1
S3:3
Power
supply
Insulated power supply
0V
+5V
B
+5V
Bus termination
0V
B
B
+5V
Bus termination
0V
B
B
A
A
A
RTS LED
MCU
230/
115V
Switch
S1