
E-922-1-E
10
(6) RS485 full duplex system (Multidrop)
TXD
RXD
Opposite
side
+
−
+
−
n = 16 max.
Terminating
resistance
110
7
9 1 0 1 1 1 2 1 3 1 4
+ − SG + − SG
RXD
TXD
Card reader n
9 1 0 1 1 1 2 1 3 1 4
+ − SG + − SG
RXD
TXD
Card reader 2
9 1 0 1 1 1 2 1 3 1 4
+ − SG + − SG
RXD
TXD
Card reader 1
4.2.3 External Terminal Connections
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
H
N
G
+
−
SG
+
−
SG
POWER
RXD
TXD
COMMUNICATION
(5) RS485 half duplex system (Multidrop)
+
−
n = 16 max.
Opposite
side
Terminating
resistance
110
7
9 1 0 1 1 1 2 1 3 1 4
+ − SG + − SG
RXD
TXD
Card reader 1
9 1 0 1 1 1 2 1 3 1 4
+ − SG + − SG
RXD
TXD
Card reader 2
9 1 0 1 1 1 2 1 3 1 4
+ − SG + − SG
RXD
TXD
Card reader n
Fig. 4.2