ICP DAS USA RS-232 Quick Start Manual page 3

Wring:
The following figure shows the wire connections of the M-Bus, RS-232,
RS-422 and RS-485. The GND pins of RS-232 and RS-422 are the same pin.
Note: Only one port of the RS-232, RS-422 and RS-485 can work at the
same time.
Bias Resistor:
In order to stable the signals of the RS-485 and RS-422 network, the bias
resistor must be applied. The factory default of the I-7590 is to enable the bias
resistor. If there is any other RS-485 (or RS-422) device which has enabled the
bias resistor, the bias resistor of the I-7590 must be disabled. Users can open the
cover of the I-7590, and adjust the SW2 for RS-485 (or SW2 and SW3 for RS-
422) to configure the bias resistor. It would be as the following figure.
I-7590 RS-232/422/485 to M-Bus Convertor - QuickStart (Mar/2017)
ICP DAS USA, Inc. | www.icpdas-usa.com
CA 90717
| 1-310-517-9888 | 24309 Narbonne Ave. Suite 200. Lomita,
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