Copyright © 2010 Future Technology Devices International Limited

8

Document Reference No.: FT_000204

DB9-USB-RS232 Datasheet

Version 1.2

Clearance No.: FTDI# 130

2.1.3 Replacing an RS232 DB9 FEMALE (DCE defined) Connector

The DB9-USB-RS232-F can be used to replace a female DB9 connector used for transmitting RS232

protocol. With the DB9-USB-RS232-F in place instead of the standard USB connector a USB bridge is

created, this allow the application to communicate with other devices via USB. Installing the DB9-USB-

RS232-F is simple. Simply replace the female DB9 connector with the DB9-USB-RS232-F connector

(same PCB footprint), install drivers and the device is ready to use.

Table 2.3 gives the pin out description of each pad of an RS232 footprint. Figure 2.3 gives a description

of the connections between the DB9-USB-RS232-F and the footprint of a female DB9 module. Figure 2.4

Illustrates the connection made to an example PCB.

Pin

Number

Pin Type of DB9-

USB-RS232

module

Pin Type at

application PCB

Description

1

Input

Output

DCD = Data Carrier Detect

(this is an input to the DB9-USB-RS232-F from

the application DCD output)

2

Input

Output

RXD = Receive Data

(this is an input to the DB9-USB-RS232-F from

the application Tx output, normally labelled RXD

in DCE convention)

3

Output

Input

TXD = Transmit Data

(this is an output to the DB9-USB-RS232-F from

the application Rx input, normally labelled TXD in

DCE convention)

4

Output

Input

DTR = Data Terminal Ready

(this is an output to the DB9-USB-RS232-F from

the application DSR input, normally labelled DTR

in DCE convention)

5

Ground

Ground

GND = RS232 signal ground

6

Input

Output

DSR = Data Set Ready

(this is an input to the DB9-USB-RS232-F from

the application DTR output, normally labelled DSR

in DCE convention)

7

Output

Input

RTS = Request To Send

(this is an output to the DB9-USB-RS232-F from

the application CTS input, normally labelled RTS

in DCE convention)

8

Input

Output

CTS = Clear To Send

(this is an input to the DB9-USB-RS232-F from

the application RTS output, normally labelled CTS

in DCE convention)

9

Input

Output

RI = Ring Indicator

(this is an input to the DB9-USB-RS232-F from

the application RI output)

Shield

Ground

Case Ground

Drain = typically connected to the host PC case

Table 2.3 – A Female RS232 DB9 footprint Pin-Out