Copyright © 2010 Future Technology Devices International Limited

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Document Reference No.: FT_000204

DB9-USB-RS232 Datasheet

Version 1.2

Clearance No.: FTDI# 130

1 Introduction

The DB9-USB-RS232 modules are designed to directly replace an existing DB9, the industry accepted

name for a DE9 connector, (male or female) RS232 connection with a drop-in USB replacement

connection. The modules will replace (pin-for-pin) a male or female DB9 RS232 connector with a USB

mini-B connector. The application PCB containing the existing DB9 RS232 connector does not require any

modification, only the replacement of the D-type connector with the appropriate DB9-USB-RS232

module. A male DB9 should be replaced by a male DB9-USB-RS232-M and a female DB9 should be

replaced by a female DB9-USB-RS232-F. The modules contain all necessary electronics to convert

between USB and RS232.

The purposes of the modules is to provide a simple method of adapting legacy serial devices with RS232

interfaces to modern USB ports by replacing the DB9 connector with this miniaturised module which

closely resembles a DB9 connector. This is accomplished by incorporating the industry standard FTDI

FT232R USB-Serial Bridge IC plus the required level shifters inside the module.

Figure 1.1 – DB9-USB-RS232

The module uses a standard USB-MINI-B connector for connection to an upstream host or hub port.

RS232-level signals, including modem handshake signals, can transmit data at rates up to 1 Mega Baud.

The DB9-USB-RS232 module requires USB device drivers, available free from www.ftdichip.com, which

are used to make the DB9-USB-RS232 appear as a Virtual COM Port (VCP). This allows existing serial

communications software, such as HyperTerminal, to exchange data through the DB9-USB-RS232 to a

legacy RS232 peripheral device.

Note: The connector is referred as a DB9 connector since DE9 is often referred to by this name.