Copyright © 2010 Future Technology Devices International Limited

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Document Reference No.: FT_000136

USB-COM485-PLUS2 Datasheet

Version 1.3

Clearance No.: FTDI#104

1.2 LED Description

The USB-COM485-PLUS2 uses three LEDs to indicate a valid link as well as data traffic according to the

following table:

LED Colour

Function

Description

Yellow x 1

Power

ON when USB-COM485-PLUS2 is configured and ready

Red x 2

TxD Activity

Flashes when data is transmitted from the USB-COM485-PLUS2 to the

attached RS485 device

Green x 2

RxD Activity

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

USB-COM485-PLUS2

Table 1.1 – LED Description

1.3 Block Diagram

FTDI FT2232H

Hi-Speed USB Serial

Bridge

RS485

Level Shifter

USB B

Client

Connector

DE-9P

Connector

RS485

Level Shifter

DE-9P

Connector

Channel A

Channel B

Figure 1.2 USB-COM485-PLUS2 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 FT2232H

FT2232H Hi-Speed USB2.0 (480Mb/s) is a dual serial UART interface IC device. Operating system device

drivers are required in order to work with the one to provide the Virtual COM Port serial functionality.

Dual RS485 Level Shifter

The RS485 level shifter converts the signals provided by the FT2232H into the voltage levels required by

RS485 devices.

DE-9P Connector (Male)

The DE-9P connector is configured in an industry standard (TIA/EIA-574) pin-out to provide connection to

RS485 peripherals through standard cables. See section 3.1.2