1 eia-232, Eia-232, Figure 4.1 – RLE FMS V.1.13 User Manual
Page 134: Table 4.1, Com1 db9 male pin out
134
FMS User Guide
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Advanced Communications - Modbus, BACnet, and Telnet
4.2.1 EIA-232
The EIA-232 COM Port 1 on the FMS is used to connect the FMS-as a Modbus Master-to one
Modbus Slave device, or it is used to connect a Modbus Master device to the FMS as a
Modbus Slave. The Modbus EIA-232 (DTE) is active over COM1 (DB9 male connector). The
EIA-232 port allows communications between the FMS and one other device (point to point
connection). The EIA-232 port has maximum cable length of 50 feet (15.2m).
Figure 4.1
FMS Modbus EIA-232 Connection to an EIA-232 DCE Device
Pin
Description
1
Data Carrier Detect
2
Receive Data
3
Transmit Data
4
Data Terminal Ready
5
Signal Ground
6
No Connection
7
Request to Send (internally connected to Pin 8)
8
Clear to Send (internally connected to Pin 7)
9
No Connection
Table 4.1
COM1 DB9 Male Pin Out