Page 13 of 26
8
RI
Ring Indicate
In
22
9
9,10
GND
Signal Ground
--
7
5
Facing the connector pins, the pinout is pictured in the following,
Table 2 Connector CN4 in RS-232 Mode (II)
9
7
5
3
1
GND
DTR
TXD
RXD
DCD
GND
RI
CTS
RTS
DSR
10
8
6
4
2
RS-422, RS-485 RTS, RS-485 Inverted RTS Serial Port Modes
When using RS-422 or RS-485 mode, you can use the port in either half-duplex (two-wire) or full-
duplex (four-wire) configurations. For half-duplex (2-wire) operation, you must connect RXD+ to
TDX+ and connect RXD- to TXD-.
Note:
120-ohm termination resistors for the RxD and CTS signals are provided on the
utilityModule. Termination is usually necessary on all RS-422 receivers and at the ends
of the RS-485 bus. If the termination resistor is required, it can be enabled by closing
jumpers labeled “R” and “C” for the corresponding port. For more information, refer to the
Jumper Settings table later in this chapter.
The following table gives the pinout of connector CN4 when RS-422 or RS-485 modes are
enabled.
Table 3 Connector CN4 in RS-422/485 Mode (I)
CN3 Pin
Signal
Function
In/out
DB9
1
RTS-
Request to send (-)
Out
1
2
RTS+
Request to send (+)
Out
6
3
RXD-
Receive Data (-)
In
2
4
TXD+
Transmit Data (+)
Out
7
5
TXD-
Transmit Data(-)
Out
3
6
RXD+
Receive Data (+)
In
8
7
CTS-
Clear to send (-)
In
4
8
CTS+
Clear to send (+)
In
9
9,10
GND
Signal Ground
--
5
