Owner`s manual

Appendix C: RS232/RS485 Adaptor Cables
C-5
RS232 Function 8-pin Connector(on
RTU)
9-pin Male Direction
GND 4 5 -
CD (Rec line)
5 ←
1 to RTU
RTS
6 →
4 from RTU
7 Not used
DTR
8 →
7 from RTU
RTU-to-RTU Connection Using MDLC Protocol through RS232
To establish a link between two RTUs using MDLC protocol, the ports of both RTUs should
be defined as RS232 RTU-to-RTU (RS-Link). The ports of the two RTUs should be connected
by the FLN6457B and FLN6458B adaptors, when the adaptors are connected.
Do not connect between RTUs without the adaptor cables. A direct connection will cause a
short circuit between the pins that have the same function.
RTU-to-RTU Synchronous Communication Using Plug-in Port
The pin assignment of the cable to be used for RTU-to-RTU synchronous communication
(using a plug-in port) is given below.
RS232 Function 8-pin Connector
(on sending RTU)
8-pin Connector
(on receiving RTU)
Direction
TX-DATA
1 → 2 ←
from RTU
RX-DATA
2 ← 1 →
to RTU
CTS
3 +6 →∗ 5 ←
from RTU
Signal GND 4 4 -
CD (Rec line)
5 ← 3 +6 →∗
to RTU
RTS
6 +3 →∗ 5 ←
from RTU
TX_CLK
7 → 8 ←
from RTU
RX_CLK
8 ← 7 →
to RTU
*Pins 3 and 6 are shorted.