
Document Reference No.: ES_000086
ES-R-2x01B-M RS-232 to RS-422/RS-485 Converters Manual
Version 1.0
Clearance No.: ES
#
42
©2010 - 2011 EasySYNC Ltd.
13
Wiring Diagrams
The diagram shows an ES-R-2x01B-M converter connected to an RS-485 half-duplex bus. If the ES-R-
2x01B-M is at one end of the bus (as shown), the built-in resistor can be enabled to terminate the Data
± lines. The Tx ± termination jumper is used to enable this resistor. A second termination resistor is
fitted at the other end of the bus as shown.
If additional unexpected zero bytes are being received, the ES-R-2x01B-M converters also features bias
resistors (not shown below) which can be enabled by enabling the
Pull-up Rx+ to VCC by 750 Ohm Bias
resistor
and
Pull-down Rx- to GND by 750 Ohm Bias resistor
) jumpers. For further details see sections
4.1 and 4.4. These should not be enabled if another device on the bus is already providing biasing.
Twisted pair wires are required for each signal pair.
Figure 6
RS-485 Half Duplex Wiring
RS-485 Devices
ES-R-2x01B-M
Data+
Data-
GND
Data+
Data-
GND
Data+
Data-
GND
Data+
Data-
GND