Emerson PACSystems RX3i - Page 137

PACSystems™ RX3i and RSTi-EP CPU Reference Manual Section 5
GFK-2222AK October 2019
Communications 129
5.2.3.5 COM2 (RS-485, 15-pin Female D-sub Connector) – All RX3i
CPU/CRU Models & RX3i CPE310
This is a DCE port that allows a simple straight-through cable to connect with a standard
AT-style RS-232 port.
5.2.3.5.1 COM2 RS-485 Signals
Pin No.
Signal Name
Description
1
Shield
Cable Shield
Located at the bottom right of the connector as viewed
from the front of the module.
2
NC
No Connection
3
NC
No Connection
4
NC
No Connection
5
+5Vdc
Logic Power: Provides isolated +5Vdc power (300mA
maximum) for powering external options.
6
RTS(A)
Differential Request to Send A
7
0V
Signal Ground
8
CTS(B‘)
Differential Clear To Send B
9
RT
70
Resistor Termination
10
RD(A‘)
70, 71
Differential Receive Data A
11
RD(B‘)
71
Differential Receive Data B
12
SD(A)
Differential Send Data A
13
SD(B)
Differential Send Data B
14
RTS(B’)
Differential Request To Send B
15
CTS(A’)
Differential Clear To Send A