Ametek 241CE II Operator's Manual page 68

Figure 3-6.
Microcontroller board
(100-1181).
3-24 | Model 241CE II Hydrocarbon Dewpoint Analyzer
The RS-485 terminals can be configured as a 4-wire RS-485, a 2-wire
RS-485, or a 4-wire RS-422 connection. The configuration is determined
by the settings of the software and the position of the JP800 and JP801
jumpers on the Microcontroller board in the Electronics Enclosure (Figure
3-6). If necessary, you can change the software settings and the jumpers to
obtain the desired serial port configuration. The jumper settings, software
settings, and terminal designations are explained under "Serial Communi-
cations Configuration" below.
The configuration settings are also discussed in Chapter 4. The default
serial port configuration is RS-232. In this configuration, RS-232 serial
communications will be active at the D-connector and terminal strip. Only
one type of serial port configuration can be functional at any given time.
Serial Communications Configuration
Communication Type
RS-422
RS-485 Line Termination
RS-485 Biased High
RS-485 Biased Low
JP800, JP801
JP800 JP801
NONE C
C C
A,B A,B
D,E D,E