USB to Serial Converters Manual
Version 2.1
Document Reference No.: CP_000032 Clearance No.: CP#022
Copyright © Connective Peripherals Pte Ltd
23
5.4
RS-485 Signal Pin-out (Full Duplex)
DB-9 Male connector
Table 21 shows the RS-485 (full duplex) pinout of the DB-9 male connector.
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
Shield
Case Ground
Drain = typically connected to the host PC case
Table 21 - RS-485 Full Duplex Pin-out for DB-9 Connector
Note:
Other pins have no function in this mode and should be left un-connected.
5-way Terminal Block
Table 22 shows the RS-485 (full duplex) pinout 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 22 - RS-485 Full Duplex Pin-out for Terminal Block
6-way Terminal Block
Table 23 below shows the RS-485 (full duplex) 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 23 - RS-485 Full Duplex Pin-out for Terminal Block
