Copyright © 2010 Future Technology Devices International Limited

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Document Reference No.: FT_000132

USB-COM485-PLUS1 Datasheet

Version 1.21

Clearance No.: FTDI# 95

1.2 LED Description

The USB-COM485-Plus1 uses three LEDs to indicate a valid link as well as data traffic according to the

following table:

LED Color

Function

Description

Yellow

Enumerated

ON when USB-COM485-Plus1 is configured and ready

Green

TxD Activity

Flashes when data is transmitted from the USB-COM485-Plus1 to the

attached RS485 device

Red

RxD Activity

Flashes when data is transmitted from the attached RS485 device to the

USB-COM485-Plus1

Table 1.1 LED Description

1.3 Block Diagram

FTDI FT232R

USB Serial Bridge

RS485

Level Shifter

USB B

Client

Connector

DE-9P

Connector

Figure 1.2 USB-COM485-Plus1 Block Diagram

1.3.1 Block description

USB B Client Connector

This connector provides the interface for connection to a USB Host or Hub port. The maximum cable

length is 5 meters, according to the USB 2.0 specification.

FTDI FT232R

The FTDI FT232R provides the USB-to-Serial conversion. Operating system device drivers are required in

order to work with the FT232R to provide the Virtual COM Port serial functionality.

RS485 Level Shifter

The RS485 level shifter converts the signals provided by the FT232R into the voltage levels required by

RS485 devices.

DE-9P Connector (Male)

The DE-9P connector is configured in an industry standard (TIA/EIA-485) pin-out to provide connection to

RS485 peripherals through standard cables. See section 3.1.2