USB to Serial Converters Manual
Version 2.1
Document Reference No.: CP_000032 Clearance No.: CP#022
Copyright © Connective Peripherals Pte Ltd
20
Shield
Case Ground
Drain = typically connected to the host PC case
Table 15 - RS-422 Pin-Out for DB-9 Connector
5-way Terminal Block
Table 16 shows the RS-422 pin-out of the 5-way terminal block (only available on some models).
Pin Number
Pin Type
Description
1
Output
TxD- = Transmit data, negative polarity
2
Output
TxD+ = Transmit data, positive polarity
3
Input
RxD+ = Receive data, positive polarity
4
Input
RxD- = Receive data, negative polarity
5
Ground
GND = Signal ground
Table 16 - RS-422 Pin-Out for 5-way Terminal Block
6-way Terminal Block
Table 17 shows the RS-422 pin-out of the 6 way terminal block (only available on some models).
Pin Number
Pin Type
Description
1
Output
TxD- = Transmit data, negative polarity
2
Output
TxD+ = Transmit data, positive polarity
3
Input
RxD+ = Receive data, positive polarity
4
Input
RxD- = Receive data, negative 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 17 - RS-422 Pin-Out for 6-way Terminal Block
Wiring Diagrams
Figure 12 shows an RS-422 full-duplex bus. The ES-U-xxxx-x has a built-in resistor for terminating its
RxD +/- input, which can be enabled using a jumper. The Tx +/- lines which are outputs from the ES-U-
xxxx-x are terminated at the receiver at the other end of the bus as shown. Twisted pair wires are
required for each signal pair.
Figure 12 - RS-422 4 Wire Full Duplex
RS-422 Device
ES-U-xxxx-x
RxD+
TxD+
RxD-
TxD-
TxD+
RxD+
TxD-
RxD-
GND
GND
