2 Procedure
The following procedure should be followed to modify the VID and/or PID in Linux. The FTDI client device
should not be connected until indicated by the procedure.
1. Open a terminal window in Linux.
2. Go to the /etc/udev/rules.d directory.
The “sudo” command can be used here to create files.
3. Using the preferred Linux text editor, create a new file with the following name:
99-usbftdi.rules
4. Enter the following Linux code, then save and close the file:
# For FTDI FT232 & FT245 USB devices with Vendor ID = 0x0403, Product ID = 0xabc
SYSFS{idProduct}==”abcd”, SYSFS{idVendor}==”0403”, RUN+=”/sbin/modprobe –q ftdisio
product=0xabcd vendor=0x0403”
Note that “0xabcd” is a dummy value for the PID; you will enter the PID assigned to you from FTDI.
For a VID assigned by the USB-IF, also modify the “idVendor” value above to match the assigned VID.
5. Save and close the rules file.
6. To instantiate, run the following command:
sudo udevcontrol_reload rules <CR>
(It is only necessary to run this command once. The rule file will always be executed at system start up.)
7. Connect the FTDI device with the customized VID/PID and enter:
 dmesg | grep FTDI <CR>
This command will confirm a successful driver load. You should see the following:
[ 15.768872] drivers/usb/serial/usb-serial.c: USB Serial support registered
for FTDI USB Serial Device
[ 15.768927] ftdi_sio 4-1:1.0: FTDI USB Serial Device converter detected
[ 15.769177] usb 4-1: FTDI USB Serial Device converter now attached to ttyUSB0
The new VID/PIDs will stay resident on the Linux PC after shutdown and restart.
Communication with the FTDI device can be set up by using a simple Linux TTY terminal and pointing it to
/dev/ttyUSB0.
8. To confirm the new VID/PID combination is present enter the following :
Document Reference No.: FT_000081
Implementing Custom FTDI VID and PID In Linux. Technical Note TN_101 Version 1.0
Clearance No.: FTDI# 64
lsusb <CR>
Bus 002 Device 001: ID 0000:0000
Bus 004 Device 004: ID 0403:abcd Future Technology Devices International, Ltd
Bus 004 Device 001: ID 0000:0000
Bus 003 Device 001: ID 0000:0000
(Note 1: lsusb does not confirm that driver is successfully loaded, only that hardware has been attached to
the computer.)
(Note 2: At the time of writing this application note, the only method available to modify the hardware (onchip)
PID/VID values is to use the Mprog3.0 application. This application only runs on Microsoft Windows)
If FTDI’s standard VID code is being used, then this MUST be used with a PID code allocated by FTDI. It is
not permissible to create user defined PID codes. In this case, please request a block of 8 unique PIDs from
FTDI (at no cost). All you need is a phone call or email to FTDI Support (refer to Contact Information
section). These allocated PIDs must be used with the standard FTDI VID of 0x0403.
If a custom VID is used (available to current members of the USB Implementers Forum USB-IF), then users
can choose any PID code. (This option has a cost associated with it).
Additional note for Ubuntu users:
It is not possible to access the Virtual COM port in Ubuntu until the “brltty” port is removed. This is done as
follows:
sudo apt-get remove brltty <CR>
Document Reference No.: FT_000081
Implementing Custom FTDI VID and PID In Linux. Technical Note TN_101 Version 1.0
Clearance No.: FTDI# 64
2.2 Acronyms and Abbreviations
Terms Description
VID/PID Vendor ID/Product ID
FTDI_SIO FTDI Virtual Com Port driver for Linux Operating Systems
sudo Linux “Substitute User” command, gives administrator privileges
kernel Code that forms the heart of a Linux Operating System
Terminal Window A Linux application similar to Windows’ “Command Prompt”
dmesg Linux “Message of the day” – shows a log of events for the Linux PC.
Table 2.1 Acronyms and Abbreviations
Document Reference No.: FT_000081
Implementing Custom FTDI VID and PID In Linux. Technical Note TN_101 Version 1.0
Clearance No.: FTDI# 64
3 Contact Information
Head Office – Glasgow, UK
Future Technology Devices International Limited
373 Scotland Street
Glasgow G5 8QB
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://apple.clickandbuild.com/cnb/shop/ftdichip
Branch Office – Taiwan
Future Technology Devices International Limited (Taiwan)
2F, No. 516, Sec. 1, NeiHu Road
Taipei 114
Taiwan , R.O.C.
Tel: +886 (0) 2 8797 1330
Fax: +886 (0) 2 8751 9737
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 97124-5803
USA
Tel: +1 (503) 547-0988
Fax: +1 (503) 547-0987
E-Mail (Sales): us.sales@ftdichip.com
E-Mail (Support) : us.support@ftdichip.com
E-Mail (General Enquiries): us.admin@ftdichip.com
Web Site URL: http://www.ftdichip.com
Distributors and Sales Representatives
Please visit the Sales Network page of the FTDI Web site for the contact details of our distributor(s) in your country.