Future Technology Devices International Ltd
USB-COM485-PLUS4
Datasheet
Document Reference No.: FT_000153
Version 1.0
Issue Date: 2009-09-14
Future Technology Devices International Ltd (FTDI)
Unit 1, 2 Seaward Place, Centurion Business Park, Glasgow, G41 1HH, United Kingdom
Tel.: +44 (0) 141 429 2777
Fax: + 44 (0) 141 429 2758
E-Mail (Support): support1@ftdichip.com Web: http://www.ftdichip.com
Neither the whole nor any part of the information contained in, or the product described in this manual, may be adapted or reproduced
in any material or electronic form without the prior written consent of the copyright holder. This product and its documentation are
supplied on an as-is basis and no warranty as to their suitability for any particular purpose is either made or implied. Future Technology
Devices International Ltd will not accept any claim for damages howsoever arising as a result of use or failure of this product. Your
statutory rights are not affected. This product or any variant of it is not intended for use in any medical appliance, device or system in
which the failure of the product might reasonably be expected to result in personal injury. This document provides preliminary
information that may be subject to change without notice. No freedom to use patents or other intellectual property rights is implied by
the publication of this document. Future Technology Devices International Ltd, Unit1, 2 Seaward Place, Centurion Business Park,
Glasgow, G41 1HH, United Kingdom. Scotland Registered Number: SC136640
Copyright © 2009 Future Technology Devices International Limited
Document Reference No.: FT_000153
USB-COM485-PLUS4 Datasheet
Version 1.0
Clearance No.: FTDI# 108
1
Introduction
1.1
Functional Description
The USB-COM485-PLUS4 is a USB to a quad interface RS485 level serial UART adaptor incorporating
FTDI’s FT4232H Hi-Speed USB2.0 (480Mb/s) to quad serial UART interface IC device. The FT4232H
handles all the USB signalling and protocols. The adaptor provides a fast, simple way to connect devices
with an RS485 interface to USB.
USB-COM485-PLUS4 is a USB to a quad-port RS485 adapter.
The integrated electronics of the USB-COM485-PLUS4 utilise the FTDI FT2232H and includes RS485 level
shifters plus TXD/RXD LEDs to provide a visual indication of data traffic through the module.
Figure 1.1 USB-COM485-PLUS4
The module uses a standard USB mini-B device connector for connection to an upstream host or hub
port. RS485-level signals are available on an industry-standard DE-9P connector. The maximum RS485-
level data rate is 10Mbps.
The USB-COM485-PLUS4 module requires USB device drivers, available free from
www.ftdichip.com,
which are used to make the USB-COM485-PLUS4 appear as a Virtual COM Port (VCP). This allows existing
serial communications software, such as HyperTerminal, to exchange data through the USB-COM485-
PLUS4 to a legacy RS485 peripheral device.
Copyright © 2009 Future Technology Devices International Limited
1
Document Reference No.: FT_000153
USB-COM485-PLUS4 Datasheet
Version 1.0
Clearance No.: FTDI# 108
1.2
LED Description
The USB-COM485-PLUS4 uses 9 LEDs to indicate a valid link as well as data traffic according to the
following table:
LED Colour
Yellow x 1
Function
Power
Description
ON when USB-COM485-PLUS4 is configured and ready
Red x 4
TxD Activity
Flashes when data is transmitted from the USB-COM485-PLUS4 to the
attached RS485 device
Flashes when data is transmitted from the attached RS485 device to the
USB-COM485-PLUS4
Green x 4
RxD Activity
Table 1.1 – LED Description
Copyright © 2009 Future Technology Devices International Limited
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Document Reference No.: FT_000153
USB-COM485-PLUS4 Datasheet
Version 1.0
Clearance No.: FTDI# 108
1.3
Block Diagram
Figure 1.2 USB-COM485-PLUS4 Block Diagram
1.3.1 Block description
USB Mini B Client Connector
This connector provides the interface for connection to a USB Host or Hub port. A standard “A to mini B”
cable is provided, though one of a different length may also be used. The maximum cable length is 5
meters, according to the USB 2.0 specification.
FTDI FT4232H
FT4232H Hi-Speed USB2.0 (480Mb/s) is a quad serial UART interface IC device. Operating system device
drivers are required in order to operate with the FT4232H in order to provide the Virtual COM Port serial
functionality.
Quad RS485 Level Shifter
The RS485 level shifter converts the signals provided by the FT4232H into the voltage levels required by
RS485 devices.
DE-9P Connector (Male)
The DE-9P connectors are configured in an industry standard (TIA/EIA-574) pin-out to provide connection
to RS485 peripherals through standard cables. See section 3.1.2
Copyright © 2009 Future Technology Devices International Limited
3
Document Reference No.: FT_000153
USB-COM485-PLUS4 Datasheet
Version 1.0
Clearance No.: FTDI# 108
1.4
Features
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Adds four RS-485 serial ports by connecting to a USB 2.0 Hi-Speed interface.
Easy plug & play installation and RS-485 device connection
Operates with USB 1.1 & 2.0 Host and Hub ports
Industry Standard FTDI chip set & device drivers for maximum compatibility
Microsoft Windows
®
WHQL-certified, Mac OS X, Linux and Windows CE device drivers
Installs as a standard Windows COM ports
COM port number can be changed to any available COM port number, to support HyperTerminal,
or any other serial communications software application running in Windows
Supports Windows Server 2008, 2003, Vista, XP, 2000, Windows CE, Linux, Mac OS X
FIFO: 2K byte transmit buffer, 2K byte receive buffer
RS-485 data signals: Data+, Data-, GND
Powered by USB port. No external power adapter required. +5V output available.
Serial port speed up to 10Mbps
Serial Communication Parameters
o
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Parity: None, Even, Odd
Data bits: 7, 8
Flow control: X-ON/X-OFF, None
Four DE-9P male connectors
LEDs indicate USB Enumeration, RxD, TxD for monitoring port status & easy diagnostics
Operating temperature of -40°C to +85°C
Echo and non-Echo two modes can be selected.
1.5
Performance Figures
Parameter
Performance
USB Interface
480Mbps USB 2.0 High-Speed
Standard Windows baud rates (300bps to 921.6Kbps)
RS485 Interface
Custom baud rates (300bps to 10Mbps) through baud rate aliasing.
See FTDI Application Note:
Configuring FT232R, FT2232 and FT232BM
Baud Rates
Max Cable Length
USB = 5m, RS485 =12m (at 10Mbps)
Table 1.2 - Performance Figures
Part Number
USB-COM485-PLUS4
Description
USB-COM-Plus Hi-Speed USB to 4-Port RS485 module
Table 1.3 - Ordering Information
Copyright © 2009 Future Technology Devices International Limited
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