All of the OP-4001, V-4001, & V-4000 interfaces are similar in regards to
driver installation. They are all Roland MPU-401 compatible, 100% compatible
- as real Roland chips were used. 
*** ALL CARDS ARE HARDWIRED TO I/O PORT ADDRESS 0330-0337 ***
(cannot be changed)
NOTE: The V-4001 is earlier than the V-4000.

* For old DOS programs (possibly other platforms, such as Linux, Unix, etc.):
  The chipset gets "initialized" by a program.  This would include Sequencer
  Plus version 3.x and earlier versions.   The reason: in this time period,
  the MPU chipset is running at 10 Mhz, which is faster than the XT and early
  AT IBM clones of its day.   The caveat: The OP-4001 also provides FSK
  (Frequency Shift Key) for sync, as well as an audio Metronome.              
  The V-4001 provides Smark FSK (Frequency Shift Key) for sync, plus the audio
  Metronome.               
  The V-4000 provides none of these extras.

* For "newer" DOS programs, etc.
  A software driver is used for MPU-401 by the host program.
  For example, Sequencer Plus (all 4.x versions) uses a "VapiMpu.com" driver.
  Only the Midi In and the Midi Out are supported.

* For any Windows, the Windows provided driver for "MPU-401" will work.
  In Windows 3.x, this driver is listed under "Roland".
  For Windows 9x and NT, this driver is listed under "Microsoft".
  Only the Midi In and the Midi Out are supported.

* For alternate O/S's, the MPU-401 is the most common Midi driver and is
  therefore usually included.   VTB does not support these platforms, but
  this is a useful fact for customers who venture into other platforms. 

* This old 80's card is definitely not PnP ( but may be detected by Windows
  sometimes.  )