nThis information comes courtesy of various people (if you are one of
these people and want to be credited contact me at bryder at pardise
dot net dot nz) who
have tried the device with a SICK laser. I (bryder) haven't had
personal experience with this. I may have made transcription errors so
be warned! 

If you want to use the device driver for the SICK laser you need to
enable a baudrate which is not supported by POSIX and hence Linux.

Here is the overview of what you must do:

 -  Choose a baudrate you won't use with the driver.

 -  Replace the value in the FTDI_8U232AM_48MHz_baudrate_t typedef
    in LINUX_SOURCE_DIR/drivers/usb/serial/ftdi_sio.h with 0x0006 -
    this value gives 500,000 kbps.

 -  Rebuild the ftdi_sio module (assuming you are using modules - rebuild
    the whole kernel otherwise and install) and load it. 

In your communication program select that baudrate you replaced and
you will get 500,000 kbps. Don't forget you MUST be using either a RS422 converter
or have very short cables/traces (and you have to be lucky) to be able to run
reliably at this baudrate. The standard RS232 physical interface is
not designed to be able to run reliably at these speeds.