SMC Networks 1232 Series user manual Function DB25, RS422 Pin, RS485, Function In/out Pin

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J5

Serial 1

J6

Serial 2

Figure 12. J5 and J6 Connectors layout

Both can be set as RS232 but only one (J5) can be set as RS422-485.

Refer to the following tables for the serial ports pinout assignment in RS232/422/485 modes.

Table 9. J5, J6 Serial Port Connectors in RS232 mode

Pin

1

2

3

4

5

6

7

8

9,10

Signal

DCD

DSR

RX

RTS

TX

CTS

DTR

RI

GND

Function	DB25	DB9
Data Carrier Detect	8	1
Data Set Ready	6	6
Receive Data	3	2
Request To Send	4	7
Transmit data	2	3
Clear To Send	5	8
Data Terminal	20	4
Ready
Ring Indicator	22	9
Signal Ground	7	5

Table 10. J5 Serial Port Connector in RS422-RS485 modes

		RS422
Pin	Signal	Function	In/out
1	-TX	Transmit data	out
2	--	Not connected	--
3	+TX	Transmit Data	out
4	--	Not connected	--
5	-RX	Receive Data	in
6	--	Not connected	--
7	+RX	Receive Data	in
8	--	Not connected	--
9,10	gnd	Signal ground	--

	RS485
Signal	Function	In/out	Pin
-TX/-RX	Transmit/Receive data	out/in	1
--	Not connected	--	2
+TX/+RX	Transmit/Receive data	out/in	3
--	Not connected	--	4
--	Not connected	--	5
--	Not connected	--	6
--	Not connected	--	7
--	Not connected	--	8
gnd	Signal ground	--	9,10

Note. If the Serial port is used in RS485 mode, the bi-directional line must be controlled via software, using the Data Terminal Ready (DTR) signal of the serial controller.

This signal is defined by bit 0 of the UART Modem Control Register (MCR) and the bi- directional line is controlled as follows:

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