5-3
5.2 RTU to Modem Connection
5.2.1
RTU-to-Modem Asynchronous Connection
For a 9-pin or 25-pin connections, use the FLN6458 cable kit to connect one of the
IRRInet-XL RTU RS-232 ports asynchronously to a modem (The RTU serves as DTE).
The kit includes a cable with RJ45 modular jacks on both ends and a RJ45 to 9-pin and
25-pin male D-Type adaptor (See Figure
5-2).
The possible RTU configurations are detailed in Table
5-1:
Table
5-1 RTU to Modem Asynchronous Connection
CPU Port No.
Used with Piggyback
Board
Toolbox Definition
2
-
RS-232 UART External Modem (MDLC)
3
FRN5724
RS-232 Asynchronous External Modem,
Full Duplex or Multi-Drop Half Duplex
N
N
o
o
t
t
e
e
:
:
1. Before transmitting, the RTU sends a RTS = on signal to the modem, and will
not transmit unless it receives a feedback CTS=on signal from the modem.
2. The RTU will not receive unless it receives a DCD = on signal from the
modem.
3. When using a modem in auto-answer mode (connected to a computer port)
for remote service, the RTU does not support the RTS/CTS protocol, as the port
is designed to operate with a local computer as well as with a modem. Refer to
the jumper settings detailed in the Utilities section of the Programming Tool Box
Operating Instructions manual.
J1
(RJ45)
J2
(25-PIN
D-TYPE)
Tx_DATA
Rx_DATA
RTS
CTS
GND
DTR
Rec_LINE (DCD)
+12V
1
2
6
3
4
8
5
7
(3)2
(2)3
(7)4
(8)5
(5)7
(4)20
(1)8
Tx_DATA
Rx_DATA
RTS
CTS
GND
DTR
Rec_LINE (DCD)
NOT USED
(9-PIN
D-TYPE)
RJ45
Connector
Pin No. 1
Pin No. 8
Figure
5-2 RJ45-to-D-Type Male Connector Adaptor
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