Rs232/Rs485 Serial Communications Port; Figure 2-5 Typical Rs232 And Rs485 Connections; Table 2-3 Serial Port Pins - Teledyne 460H NEMA Instruction Manual

2.4.4 RS232/RS485 Serial Communications Port

A bi-directional RS232/485 Serial Port Interface is provided that can be used for data
acquisition and instrument control. All that is required to use this interface is a computer
with a serial communications port (COM port) and terminal software. Three pins are
provided on the I/O connector for serial communications as shown in Table 2-3.
Label
SERIAL TX
SERIAL RX
SERIAL GND
The Serial Port can be configured for either RS232 or RS485. The standard factory
configuration is RS232. For direct connection to a PC or Laptop, RS232 should be used.
For a permanent connection into a data acquisition system, RS485 is recommended
because it has better noise immunity and is more reliable when communicating over
longer distances. See Appendix A for details on changing the Serial Port configuration.
Figure 2-5 below shows typical connections using RS232 and RS485. Note that the
RS485 connection does not use the SERIAL GND pin.
SERIAL GND
SERIAL RX
SERIAL TX
SERIAL TX
SERIAL RX

Figure 2-5 Typical RS232 and RS485 Connections

See Chapter 5 for information on the Serial Communications protocol used by the
M460H.
P/N 03662D Teledyne API Model 460H O 3 Monitor Operator Manual - Page 17

Table 2-3 Serial Port Pins

Description
Serial Transmit (RS485 – A)
Serial Receive (RS485 – B)
Serial Ground (RS232 Only)
RS232
RS485
DB9-FEMALE
RS485-A
RS485-B