Future Technology Devices International Ltd
USB to RS485 Serial Converter Cable
Datasheet
Document Reference No.: FT_000117
Version 1.3
Issue Date: 18-12-09
Future Technology Devices International Limited (FTDI)
Unit1, 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
Copyright © 2010 Future Technology Devices International Limited
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 © 2010 Future Technology Devices International Limited
Document Reference No.: FT_000117
USB TO RS485 SERIAL CONVERTER CABLE Datasheet
Version 1.3
Clearance No.: FTDI #75
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Description
The USB-RS485 cable is a USB to RS485 levels serial UART converter cable incorporating FTDI‟s
FT232RQ USB to serial UART interface IC device which handles all the USB signalling and protocols. The
cable provides a fast, simple way to connect devices with a RS485 interface to USB.
Each USB-RS485 cable contains a small internal electronic circuit board, utilising the FT232R, which is
encapsulated into the USB connector end of the cable. The FT232R datasheet, DS_FT232R, is available at
http://www.ftdichip.com. The integrated electronics also include the RS485 transceiver plus Tx and Rx
LEDs which give a visual indication of traffic on the cable (if transparent USB connector specified).
The other end of the cable is bare, tinned wire ended connections by default, but can be customised
using different connectors to support various applications.
The USB-RS485 cable is designed for use at the end of an RS485 network up to approximately 10m. For
longer networks or placement of the USB-RS485 cable in the middle of an RS485 network it is
recommended that the attached wire is cut to 20cm or less to ensure signal integrity
Cables are FCC, CE, RoHS compliant.
The cable is USB powered and USB 2.0 full speed compatible. Each cable is 1.8m long and supports a
data transfer rate up to 3 Mbaud. Each cable supports the FTDIChip-ID™, with a unique USB serial
number programmed into the FT232R. This feature can be used to create a security or password
protected file transfer access using the cable. Further information and examples on this feature are
available at http://www.ftdichip.com under FTDIChip-ID Projects.
The USB-RS485 cables require USB drivers, available free from http://www.ftdichip.com, which are
used to make the FT232R in the cable appear as a virtual COM port (VCP). This then allows the user to
communicate with the USB interface via a standard PC serial emulation port (for example TTY). Another
FTDI USB driver, the D2XX driver, can also be used with application software to directly access the
FT232R on the cable though a DLL. This is illustrated in the Figure 1.1
Various Connector
Options
VCP
TTY
Wire Ended
USB_RS485
USB
Customised connectors
Virtual COM Port
Various Connector
Options
Wire Ended
D2XX
DLL
TTY
USB
Customised connectors
Software application access to USB via D2XX
Figure 1.1 Using the USB-RS485 Cable
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Cable Part Numbers
The following
Table 2.1 gives details of the available USB-RS485 cables.
Part Number
Description
USB to UART cable with RS485
USB-RS485-WE-1800-BT
level UART signals. Black cable,
Transparent USB connector
End Connector*
Wire Ended (no
connector)
Cable details
1.8m cable,6 core,
UL2464 24 AWG,
diam=5mm
USB to UART cable with RS485
level UART signals.
*
C = cable colour (B black or T
USB-RS485-CC-LLLL-CU-
transparent),
X
LLLL = Length of
CC = Connector
cable.
description.
U = USB connector colour (T
transparent or B black)
X = voltage (P is 5V, G is 0V)
Table 2.1 USB-RS485 Cables Descriptions and Part Numbers
*
FTDI supports customised end connector designs. For more information, please contact FTDI Sales Team
(sales1@ftdichip.com)
2.1 Certifications
FTDI USB-RS485 cable is fully RoHs compliant as well as CE and FCC certified.
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Table of Contents
1
Description ..................................................................................... 1
2
Cable Part Numbers ........................................................................ 2
2.1
3
Certifications ................................................................................................. 2
Typical Applications ........................................................................ 4
3.1
Driver Support .............................................................................................. 4
3.2
Features ........................................................................................................ 4
4
Features of FT232R applicable to USB-RS485 Cable ....................... 5
5
USB-RS485-WE-LLLL-CU-X ............................................................. 6
5.1
USB-RS485-WE Connections and Mechanical Details ..................................... 6
5.2
USB-RS485-WE Cable Signal Descriptions ..................................................... 7
5.3
USB-RS485-WE Electrical Parameters ........................................................... 7
5.4
Local Echo ..................................................................................................... 8
6
Cable PCB Block Diagram................................................................ 9
7
USB-RS485 – Schematic ............................................................... 10
8
Contact Information ..................................................................... 11
Appendix A - Cable EEPROM Configuration ......................................... 13
Appendix B - List of Figures and Tables.............................................. 14
Appendix C - Revision History ............................................................ 15
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USB TO RS485 SERIAL CONVERTER CABLE Datasheet
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Typical Applications
USB to serial RS485 level converter.
USB Instrumentation PC interface.
Upgrading legacy peripherals to USB.
USB industrial control.
Interface Microcontroller UART or I/O to USB.
USB password protected file transfers.
Interface FPGA or PLD to USB.
3.1 Driver Support
Royalty free VIRTUAL COM PORT
Royalty free D2XX Direct Drivers
(VCP) DRIVERS for...
(USB Drivers + DLL S/W Interface)
Windows 7 64-bit
Windows 7 64-bit
Windows XP and XP 64-bit
Windows XP and XP 64-bit
Windows Vista and Vista 64-bit
Windows Vista and Vista 64-bit
Windows XP Embedded
Windows XP Embedded
Windows 98, 98SE, ME, 2000, Server 2003,
and Server 2008
Windows 98, 98SE, ME, 2000, Server 2003,
and Server 2008
Windows CE 4.2, 5.0 and 6.0
Windows CE 4.2, 5.0 and 6.0
Mac OS 8/9, OS-X
Linux 2.4 and greater
Linux 2.4 and greater
Mac OS-X
The drivers listed above are all available to download for free from www.ftdichip.com. Various 3rd
Party Drivers are also available for other operating systems - see www.ftdichip.com for details.
3.2 Features
USB-RS485 converter cable provides a USB to
RS485 serial interface with customised end
connectors.
Entire USB protocol handled by the electronics
in the cable.
EIA/TIA-485 communication interface with low
power requirements.
UART interface support for 7 or 8 data bits, 1
or 2 stop bits and odd / even / mark / space /
no parity.
Internal EEPROM with user writeable area.
FTDI‟s royalty-free VCP allow for
communication as a standard emulated COM
port and D2XX „direct‟ drivers provide DLL
application programming interface.
Visual indication of Tx and Rx traffic via LEDs in
the transparent USB connector.
X-On / X-Off software handshaking.
Data transfer rates from 300 baud to 3 Mbaud.
Support for FT232R FTDIChip-ID™ feature for
improved security.
Low USB bandwidth consumption.
UHCI / OHCI / EHCI host controller compatible.
USB 2.0 Full Speed compatible.
-40°C to +85°C operating temperature range.
Cable length is 1.80m (6 feet).
ESD Protection for RS-485 I/O's
±15kV Human Body Model (HBM)
±15kV EN61000-4-2 Air Gap Discharge
±8kV EN61000-4-2 Contact Discharge
FCC and CE compliant.
Custom versions available on request (subject
to MOQ).
RoHS Compliant
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Features of FT232R applicable to USB-RS485 Cable
The USB-RS485 cable uses FTDI‟s FT232RQ USB to serial UART IC device. This section summarises the
key features of the FT232RQ which apply to the USB-RS485 USB to serial RS485 converter cables. For
further details, and a full features and enhancements description consult the FT232R datasheet. This is
available from www.ftdichip.com.
Internal EEPROM. The internal EEPROM in each cable is used to store USB Vendor ID (VID), Product ID
(PID), device serial number, product description string and various other USB configuration descriptors.
Each cable is supplied with the internal EEPROM pre-programmed as described in Appendix A –Cable
EEPROM Configuration. The internal EEPROM descriptors can be programmed in circuit, over USB
without any additional voltage requirement. It can be programmed using the FTDI utility software called
MPROG, which can be downloaded from FTDI Utilities on the FTDI website (www.ftdichip.com).
Additionally, there is a user area of the internal EEPROM available to system designers to allow storing of
data (note that this is not modified by MPROG).
Lower Operating and Suspend Current. The FT232R has a low 15mA operating supply current and a
very low USB suspend current of approximately 70μA. (Note that during suspend mode, the current
drawn by any customised cable application which uses the USB supply, should not exceed 2.5mA to
remain USB compliant)
Low USB Bandwidth Consumption. The USB interface of the FT232R, and therefore the USB-RS485
cables has been designed to use as little as possible of the total USB bandwidth available from the USB
host controller.
FTDIChip-ID™. The FT232R includes the new FTDIChip-ID™ security dongle feature. This FTDIChip-ID™
feature allows a unique number to be burnt into each cable during manufacture. This number cannot be
reprogrammed. This number is only readable over USB can be used to form the basis of a security dongle
which can be used to protect any customer application software being copied. This allows the possibility
of using the USB-RS485 cables as a dongle for software licensing. Further to this, a renewable license
scheme can be implemented based on the FTDIChip-ID™ number when encrypted with other information.
This encrypted number can be stored in the user area of the FT232R internal EEPROM, and can be
decrypted, then compared with the protected FTDIChip-ID™ to verify that a license is valid. Web based
applications can be used to maintain product licensing this way. An application note, AN232R-02,
available from FTDI website (www.ftdichip.com) describes this feature.
Improved EMI Performance. The USB-RS485 cables are FCC and CE certified.
Extended Operating Temperature Range - The USB-RS485 cables are capable of operating over an
extended temperature range of -40º to +85º C thus allowing them to be used in automotive or industrial
applications.
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USB-RS485-WE-LLLL-CU-X
The USB-RS485-WE cable is un-terminated; it has bare and tinned wires.
The LLLL specifies the length of the cable in cm. The CU specifies the colour of the cable and the colour of
the USB connector. The cable can be either Black or transparent. The USB connector comes default as
transparent because of LED implemented inside the plug but can be sold in black colour as well. For
simplicity, the LLLL and CU have been dropped from the following descriptions.
The cable outputs 5V power on the wire by default. This can be modified to output 0V power. The letter X
in the part number indicates the output power selection.
5.1 USB-RS485-WE Connections and Mechanical Details
The following Figure 5.1 shows the cable signals and the wire colours for the signals on the USB-RS485WE cable.
0V or +5V (default is +5V)
Figure 5.1 USB-RS485-WE Connections
Figure 5.2 USB-RS485-WE Mechanical Details (dimensions in mm)
Figure 5.3 USB-RS485-WE Cable images
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5.2 USB-RS485-WE Cable Signal Descriptions
Colour
Name
Type
Description
Black
GND
GND
Device ground supply pin.
Pin 1 of 120R Terminating Resistor. Only Required if
Brown
Terminator 1
Input
the USB-RS485-WE cable is the first or last device
in a multi-drop RS485 System, to meet RS485
Termination Requirements.
Default output is +5V when active, 0V during
suspend.
Red
POWER
Output
Power output can be customized to 0V, if required,
contact FTDI Sales Team (sales1@ftdichip.com).
Switchable power to external device, 250mA max.
OFF during suspend
Orange
Data+ (B)
Bi-Direction
Data + (B) Signal
Yellow
Data- (A)
Bi-Direction
Data – (A) Signal
Pin 2 of 120R Terminating Resistor. Only Required if
Green
Terminator 2
Input
the USB-RS485-WE cable is the first or last device
in a multi-drop RS485 System, to meet RS485
Termination Requirements.
Table 5.1 USB-RS485-WE Cable Signal Descriptions
5.3 USB-RS485-WE Electrical Parameters
Parameter
Description
Minimum
Typical
Maximum
Units
Conditions
This only applies when
cable has been configured to
VCC_5V
Output Power Voltage*
4.25
5.0*
5.25
V
output 5V. The range is
dependent on the USB port
that the USB-RS485-WE is
connected to
IO
T
Output Power Current***
Operating Temperature
Range
-
250
-40
+85
mA
Must be less that 2.5mA
during suspend.
o
C
Table 5.2 USB-RS485-WE I/O Operating Parameters
*Default is 5V.
***Only applies when POWER output is 5V.
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Parameter
Description
Minimum
Typical
Maximum
Units
+12
V
Conditions
Receiver Input
VCM
Common-mode input
-7
voltage range
1.0
IN
VIN = +12V
Input Current
mA
–0.8
VTH
VIHYST
RIN
DIfferential Threshold
-0.2
Voltage,VTH
Input Hysteresis
Input Resistance, RIN
12
VIN = –7V
+0.2
V
20
mV
15
kΩ
Transmitter Output
VOD
DIfferential Output Voltage,
dVOD
1.5
5
V
With RL = 54Ω. CL = 50pF *
Table 5.3 USB-RS485-WE I/O Pin Characteristics
* - The 54 ohms is the equivalent of two 120 ohm termination resistors placed on each side of the
transmission line and the input impedance of 32 receivers on the line.
Description
Conditions
Minimum
Typical
ESD HBM
RS-485 Inputs and Outputs
±15 kV
EN61000-4-2ContactDischarge
RS-485 Inputs and Outputs
±8 kV
EN61000-4-2AirGapDischarge
RS-485 Inputs and Outputs
±15 kV
Maximum
Table 5.4 USB-RS485-WE ESD Tolerance
5.4 Local Echo
RS485 systems often have local echo enabled. This means any data transmitted by a device is echoed
back to itself.
The USB-RS485-WE cable allows for local echo to be enabled/disabled by changing a bit in the FT232R
EEPROM. If CBUS4 in the EEPROM is set for “PWRON#” local echo is enabled. If CBUS4 in the EEPROM is
set for “TXDEN” local echo is disabled.
Users can set this with MPROG from www.ftdichip.com
The default for the local echo is disabled (CBUS4 set for “TXDEN).
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Cable PCB Block Diagram
The block diagram for the small internal electronic circuit board, utilising the FTDI FT232R, which is
encapsulated into the USB connector end of the cable, is shown in Figure 6.1.
Customised versions of the cable are also available. Users interested in customised versions of these
cables should contact FTDI sales (sales1@ftdichip.com).
VBUS
USB A
CONNECTOR
RXD
USB_DM
FT232R
Transceiver
USB_DP
GND
TXD
120 Ohm
120 Ohm
Data- (A)
Data+ (B)
Power
GND
Wire Ended
Figure 6.1 Block diagram of PCB Used in the USB to RS485 Serial Converter Cable
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USB-RS485 – Schematic
Schematic for converter cable, USB-RS485 is shown below in figure 7.1
Figure 7.1 Schematic of USB-RS485 Converter Cable
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Contact Information
Head Office – Glasgow, UK
Future Technology Devices International Limited
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 (Sales) sales1@ftdichip.com
E-mail (Support) support1@ftdichip.com
E-mail (General Enquiries) admin1@ftdichip.com
Web Site URL http://www.ftdichip.com
Web Shop URL http://www.ftdichip.com
Branch Office – Shanghai, China
Future Technology Devices International Limited (China)
Room 408, 317 Xianxia Road,
ChangNing District,
ShangHai, China
Tel: +86 (21) 62351596
Fax: +86(21) 62351595
E-Mail (Sales): cn.sales@ftdichip.com
E-Mail (Support): cn.support@ftdichip.com
E-Mail (General Enquiries): cn.admin1@ftdichip.com
Web Site URL: http://www.ftdichip.com
Branch Office – Taipei, Taiwan
Future Technology Devices International Limited (Taiwan)
2F, No. 516, Sec. 1, NeiHu Road
Taipei 114
Taiwan , R.O.C.
Tel: +886 (0) 2 8791 3570
Fax: +886 (0) 2 8791 3576
E-mail (Sales)
tw.sales1@ftdichip.com
E-mail (Support)
tw.support1@ftdichip.com
E-mail (General Enquiries) tw.admin1@ftdichip.com
Web Site URL
http://www.ftdichip.com
Branch Office – Hillsboro, Oregon, USA
Future Technology Devices International Limited (USA)
7235 NW Evergreen Parkway, Suite 600
Hillsboro, OR 97123-5803
USA
Tel: +1 (503) 547 0988
Fax: +1 (503) 547 0987
E-Mail (Sales)
us.sales@ftdichip.com
E-Mail (Support) us.admin@ftdichip.com
Web Site URL
http://www.ftdichip.com
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Distributor and Sales Representatives
Please visit the Sales Network page of the FTDI Web site for the contact details of our distributor(s) and
sales representative(s) in your country.
Vinculum is part of Future Technology Devices International Ltd. 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, Unit
1, 2 Seaward Place, Centurion Business Park, Glasgow G41 1HH United Kingdom. Scotland Registered Number: SC136640
Copyright © 2010 Future Technology Devices International Limited
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Appendix A - Cable EEPROM Configuration
Each USB-RS485 cable is controlled by the FTDI FT232R IC. This FT232R device contains an EEPROM
which contains the USB configuration descriptors for that device. When the cable is plugged into a PC or a
USB reset is performed, the PC will read these descriptors. The default values stored into the internal
EEPROM are defined in Table 0.1
Parameter
Value
USB Vendor ID (VID)
0403h
FTDI default VID (hex)
USB Product UD (PID)
6001h
FTDI default PID (hex)
Serial Number Enabled?
Notes
Yes
A unique serial number is generated and programmed into
Serial Number
See Note
the EEPROM during device final test.
Enabling this option will make the device pull down on the
Pull down I/O Pins in USB
Suspend
Disabled
is high).
Manufacturer Name
FTDI
Product Description
See note
Max Bus Power Current
Power Source
Device Type
UART interface lines when the power is shut off (PWREN#
USB-RS485-WE
250mA
Bus Powered
FT232R
Returns USB 2.0 device description to the host.
USB Version
0200
Note: The device is a USB 2.0 Full Speed device (12Mb/s)
as opposed to a USB 2.0 High Speed device (480Mb/s).
Remote Wake Up
Disabled
High Current I/Os
Enabled
Load VCP Driver
Enabled
Invert TXD
Disabled
Signal on this pin becomes TXD# if enable.
Invert RXD
Disabled
Signal on this pin becomes RXD# if enable.
Invert RTS#
Disabled
Signal on this pin becomes RTS if enable.
Invert CTS#
Disabled
Signal on this pin becomes CTS if enable.
Enables the high drive level on the UART and CBUS I/O
pins.
Makes the device load the VCP driver interface for the
device.
Table 0.1 Default Internal EEPROM Configuration
The internal EEPROM in the cable can be re-programmed over USB using the utility program MPROG.
MPROG can be downloaded from the www.ftdichip.com. Version 2.8a or later is required for the FT232R
chip. Users who do not have their own USB Vendor ID but who would like to use a unique Product ID in
their design can apply to FTDI for a free block of unique PIDs. Contact FTDI support for this service.
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Appendix B - List of Figures and Tables
List of Figures
Figure 1.1 Using the USB-RS485 Cable......................................................................................................... 1
Figure 5.1 USB-RS485-WE Connections ....................................................................................................... 6
Figure 5.2 USB-RS485-WE Mechanical Details (dimensions in mm) ......................................................... 6
Figure 5.3 USB-RS485-WE Cable images...................................................................................................... 6
Figure 6.1 Block diagram of PCB Used in the USB to RS485 Serial Converter Cable ............................. 9
Figure 7.1 Schematic of USB-RS485 Converter Cable .............................................................................. 10
List of Tables
Table 2.1 USB-RS485 Cables Descriptions and Part Numbers................................................................... 2
Table 5.1 USB-RS485-WE Cable Signal Descriptions .................................................................................. 7
Table 5.2 USB-RS485-WE I/O Operating Parameters ................................................................................... 7
Table 5.3 USB-RS485-WE I/O Pin Characteristics ........................................................................................ 8
Table 5.4 USB-RS485-WE ESD Tolerance ..................................................................................................... 8
Table 0.1 Default Internal EEPROM Configuration ..................................................................................... 13
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Appendix C - Revision History
Version Draft
First Draft
Jan, 2009
Version 1.0
First Release
11th Feb, 2009
Version 1.1
Added and corrected images
14th May 2009
Version 1.2
Corrected
default state of the power pin
Added Windows 7 64-bit
Version 1.3
Added Description – Length of the cable/wire recommendations
29th October 2009
Changed TT to BT (Transparent to Black cable)
18th December 2009
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