USB to Serial Converters Manual
Version 2.0
Document Reference No.: CP_000032 Clearance No.: CP#022
Copyright © Connective Peripherals Pte Ltd
39
2
Out / In
Data+ = Transmit / Receive Data, positive polarity
5
See
Description
For ES-U-2101-M, pin 5 is GND
For ES-U-3001-MB, pin 5 is optional 5VDC output
For ES-U-2101-MB, pin 5 is optional 5VDC output
6
Ground
GND = Signal ground
Table 19 - RS-485 Half-Duplex Pin-out for 6-way Terminal Block
Note:
Other terminals have no function in this mode and should be left un-connected.
Wiring Diagrams
The diagram shows an ES-U-xxxx-x converter connected to an RS-485 half-duplex bus. If the ES-U-xxxx-
x 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 or DIP switch 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, some models of ES-U-xxxx-x converter also
features bias resistors (not shown below) which can be enabled by fitting the
Pull up Tx+ to VCC
and
Pull
down Tx- to GND
jumpers. 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 26 - RS-485 Half Duplex Wiring
RS-485 Devices
ES-U-xxxx-x
Data+
Data-
GND
Data+
Data-
GND
Data+
Data-
GND
Data+
Data-
GND
