National Instruments Fieldpoint CFP-2220 - Manual (Page 22)

cFP-2200/2210/2220 22 ni.com
COM 4 (cFP-2220 Only)
COM 4 is an RS-485 serial port with a 10-position modular jack. The Serial
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 26 and Table 2 for pin locations and signal descriptions.
Figure 26. 10-Position Modular Jack Pin Locations
Table 2. 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