Chapter 3
Feature Descriptions
cFP-20xx and cFP-BP-x User Manual
3-8
ni.com
COM 3 (cFP-2020 Only)
COM 3 is an RS-232 DTE serial port with a 10-position modular jack. The
Serial Port VIs access COM 3 as port 2. Refer to Figure 3-3 and Table 3-3
for pin locations and signal descriptions.
COM 4 (cFP-2020 Only)
COM 4 is an RS-485 serial port with a 10-position modular jack. The Serial
Port VIs access COM 4 as port 3. COM 4 has 100 V
rms
of operational
isolation. Use an external RS-485 isolator if your application requires more
isolation. Refer to Figure 3-3 and Table 3-3 for pin locations and signal
descriptions.
Figure 3-3.
10-Position Modular Jack Pin Locations
Table 3-3.
10-Position Modular Jack Pin Descriptions
10-Position
Modular Jack Pin
RS-232 Signal
RS-485 Signal
10
DCD
GND
9
RXD
CTS+ (HSI+)
8
TXD
RTS+ (HSO+)
7
DTR
RXD+
6
GND
RXD–
5
DSR
CTS– (HSI–)
4
RTS
RTS– (HSO–)
3
CTS
TXD+
2
RI
TXD–
1
No Connect
No Connect
Pin 10
Pin 1
