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6
7
8
9
1
2
3
4
5
3-2
Section
Connecting Link Adapters
27
RS-232C Connector
The connector hood is connected to the RS-422A terminal block’s frame ground
terminal.
Pin
Signal name
Code
Signal direction
(RS-232C Device
⇔
Link Adapter)
1
Not used
---
---
2
Send data
SD
RS-232C Device
←
Link Adapter
3
Receive data
RD
RS-232C Device
→
Link Adapter
4
Request to send
(shorted to CS internally)
RS
RS-232C Device
←
Link Adapter
5
Clear to send
(shorted to RS internally)
CS
RS-232C Device
→
Link Adapter
6
+5 V (150 mA) input for Link
Adapter
+5 V
RS-232C Device
→
Link Adapter
7
Data set ready
(shorted to ER internally)
DR
RS-232C Device
→
Link Adapter
8
Data terminal ready
(shorted to DR internally)
ER
RS-232C Device
←
Link Adapter
9
Signal ground
SG
---
The following diagram shows the internal block diagram of the NT-AL001-E Link
Adapter. Refer to this diagram only when wiring custom cables or connecting
devices with special interfaces.
SW1-6
Terminating
resistance
R
R
D-SUB 9-pin
Case
+5 V
SG
SD
RD
RS
CS
DR
ER
6
9
2
3
4
5
7
8
POWER
Indicator
RS-232C
Dr/Rec
RS-422A/485 Dr/Rec
DC-DC
IS_5 V
IS_0 V
FG
1
2
3
4
6
5
7
8
SW1-5
SW1-4
SG
SDB
SDA
RDB
RDA
CSB
CSA
SW1-2
RS-422A Dr
SW1-3
RS-232C side
Fuse
Convertor
RS-422A/485 side
8 terminal block
Photocoupler
2-wire/
4-wire
R
R
R
R
L
L
REG
When using RS-422A or RS-485 cables for long-distance communications, do
not ground the shield at both ends of the communications line because large cur-
rents can flow through the shield due to the difference in potential at the two
Block Diagram
RS-422A/485 Cable
Shield Connections