CM312 Datasheet, PDF (25/56 Pages) List of Unclassifed Manufacturers – Communications utilityModule

RS232 Serial Port (Default)
The full-duplex RS232 mode is the default setting on the utilityModule. With this mode enabled,
connector CN3 must be connected to RS232 compatible devices. The following table gives the
connector pinout and shows how to connect to an external serial connector, either DB25 or DB9
compatible.
Connector CN3 in RS-232 Mode
Table 7 Connector CN3 in RS-232 Mode
CN3 Pin
Signal
Function
In/out
DB25
DB9
1
DCD
Data Carrier Detect
In
8
1
2
DSR
Data Set Ready
In
6
6
3
RXD
Receive Data
In
3
2
4
RTS
Request To Send
Out
4
7
5
TXD
Transmit Data
Out
2
3
6
CTS
Clear To Send
In
5
8
7
DTR
Data Terminal Ready
Out
20
4
8
RI
Ring Indicate
In
22
9
9,10
GND
Signal Ground
--
7
5
9
GND
GND
10
Facing the connector pins, the pinout is pictured in the following,
Table 8 Connector CN3 pin location in RS-232 Mode
7
5
3
DTR
RI
TXD
CTS
RXD
RTS
8
6
4
1
DCD
DSR
2
CM312 Quad Serial utilityModule
15
RTD Embedded Technologies, Inc.