Control Microsystems SCADAPack 350 - RS-232 Wiring Examples; Figure 11: RS-232 DTE to RS-232 DTE Without Handshaking; Figure 12: RS-232 DTE to RS-232 DTE with Handshaking

10.1.3 RS-232 Wiring Examples
10.1.3.1 DTE to DTE without Handshaking
There are several methods for wiring the RS-232 COM port to DTE (Data Terminal Equipment) and
DCE (Data Communications Equipment) devices. The simplest connection requires only 3 wires:
RxD, TxD and signal ground. The following diagram shows a common RS-232 COM port to DTE
device.
RS-232 COM port (DTE)
8 Pin connector
DTE
5
6
3
4
8
7
1
2
DCD
Rx D
TxD
DT
R
GND
RT
S
CT
S
+5V
DCD
RxD
TxD
DTR
GND
RTS
CTS
See device
specification
s
for pin number
s
Figure 14: RS-232 DTE to RS-232 DTE without Handshaking
10.1.3.2 DTE to DTE with Handshaking
Some DTE devices may require hardware handshaking lines. The most common are the CTS and
RTS lines. Less common are the DTR and DCD lines. The controller does not require these lines.
Refer to the specifications of the external device for exact requirements. The following diagram
shows a common connection of an RS-232 COM port with a DTE device requiring handshaking
lines.
RS-232 COM port (DTE)
8 Pin connector
DTE
5
6
3
4
8
7
1
2
DCD
RxD
TxD
DT
R
GND
RT
S
CT
S
+5V
DCD
Rx D
TxD
DTR
GND
RTS
CTS
See d e v i c
e
specification
s
for pin number
s
Figure 15: RS-232 DTE to RS-232 DTE with Handshaking
SCADAPack 350 Hardware Manual
February 14, 2007
35