Copyright © 2010 Future Technology Devices International Limited

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Document Reference No.: FT_000135

USB-COM422-PLUS2 Datasheet

Version 1.2

Clearance No.: FTDI#103

2 Installation

2.1.1 Wiring

Insert the A-plug into an available USB Host or Hub port. Insert the mini-B-plug into the USB mini-B-

receptacle on the USB-COM422-PLUS2.

The USB-COM422-Plus2 follows EIA-422 standard as a Data Terminal Equipment (DTE) device. If the

RS422 equipment being connected is a Data Communication Equipment (DCE) device, it’s typical that a

straight-through cable can be used.

DTE Pin Number

Signal Name

Expected Connect Signal

1

TXD- = Transmit Data,

negative polarity

RXD-

2

TXD+ = Transmit Data,

positive polarity

RXD+

3

RXD+ = Receive Data,

positive polarity

TXD+

4

RXD- = Receive Data,

negative polarity

TXD-

5

GND = signal ground

GND

6

RTS- = Request To Send,

negative polarity

CTS-

7

RTS+ = Request To Send,

positive polarity

CTS+

8

CTS+ = Clear To Send,

positive polarity

RTS+

9

CTS- = Clear To Send,

negative polarity

RTS-

Table 2.1 – RS422 DTE to DCE connection with straight-through cable

Some serial devices may require certain handshake signals to be connected. Refer to your device manual

for cabling details.