Installation
24
User’s Manual - SM19202 Fast Poll Modem
Connecting to an RS-232 Device
The modem back panel provides a female, 9-pin RS-232 connector that accepts an attached
RS-232 device (see Figure 2-2 on page 10). This connector accepts a standard connection
to a DTE (RTU) that conforms to the pin assignments shown under Table B-2 “RS-232
(DTE) Interface” in Appendix B.
1
2
3
4
5
6
7
8
9
Connecting to an RS-485 Device
The modem rear panel provide an RJ-11C module jack connector for a 4-pin RS-485 or RS-
422 interface in the event that your DTE or RTU does not support the RS-232 interface (see
Figure 2-2 on page 10 and Figure 2-7). The RS-485 interface supports 4-wire full duplex or
2-wire half duplex.
The pin assignments for the RS-485 interface are listed in Table 2-5.
Pin #6
Pin #1
Figure 2-7. Pin Locations on the Modem’s RJ-11C Jack
Table 2-5. RJ-11C Modular Jack Pin Assignments
RJ-11 Pin Number…
Corresponds to Signal Name
Modem Input or Output
1
Not Used
NA
2
RxD+
Output
3
RxD-
Output
4
TxD+
Input
5
TxD-
Input
6
Not Used
NA
