Here is 5 drivers compatible with FTDIBUS\COMPORT&VID_0403&PID_6001.
This is Device ID of D-Link USB Serial Port.
Software type:Driver
File Size:7.54Mb (7902187 bytes)
Released:10 Jan 2013
System:Windows VistaWindows Vista 64-bitWindows XPWindows XP 64-bitWindows Server 2003Windows Server 2003 64-bitWindows MELinuxWindows CEWindows 7Windows 7 64-bitWindows Server 2008Windows Server 2008 64-bit
Description:Driver for Espada MP232R2Download Espada MP232R2 Driver
Hardware:OmniBook xe3L-gf
Software name:Pavilion Notebook N54XX (GF) and HP Omnibook XE3 (GF) ? USB to Serial Adapter Driver
File Size:608.28Kb (622881 bytes)
Released:10 Jul 2002
System:Windows 98
Description:Pavilion Notebook N54XX (GF) and HP Omnibook XE3 (GF) ? USB to Serial Adapter Driver for HP OmniBook xe3L-gf

Type: Driver
This package contains a driver for Windows 98SE. This package will (by default) load the driver into the C:HPDRIVERSW98UPDATEUSB2SerYGi subdirectory, and open a read me file containing installation information.
Download OmniBook xe3L-gf Pavilion Notebook N54XX (GF) and HP Omnibook XE3 (GF) ? USB to Serial Adapter Driver 1.0
Manufacturer:Cables To Go
Hardware:USB to Serial DB9 Adapter (26478)
Software type:Driver
File Size:404.45Kb (414157 bytes)
Released:23 Mar 2010
System:Windows VistaWindows XPWindows 2000
Description:Port Authority USB to Serial 2-Port or 4-port DB9 Adapter. For parts 26478 and 26479 Driver Installer. Double-click executable to run, then plug-in adapter.

32-bit driver version available for Windows 2000, Windows XP, Windows Vista or 64-bit driver version for Windows XP, Windows Vista.
Download Cables To Go USB to Serial DB9 Adapter (26478) Driver
Manufacturer:Ambir Technology
Software type:Driver
File Size:478.92Kb (490412 bytes)
Description:OmniPort USB Univ. Port Rep
Supports the following: 33003
Download Ambir Technology 33003 Driver
Software type:Driver
File Size:322.02Kb (329752 bytes)
System:Windows VistaWindows XPWindows 2000Windows MEWindows 98 SE
Description:DA-70118 Driver for Windows 98SE/ ME/ 2000/ XP/ VistaDownload DIGITUS DA-70118 Driver