Voyetra's VAPI Driver architecture was outlined in an SDK or "Developer Kit"

[chrisNova777]

http://raympoon.playgroundhk.com/bbs/midic.htm
the following quote is referencing this software package
+ midi cable kit for the sound blaster card:
http://www.oldschooldaw.com/forums/index.php?topic=4445.0

it tips us off to the existance of this developer only kit

SB MIDI Box will also include Voyetra's Application Interface (VAPI) for the Sound Blaster, allowing programs written for the Yamaha C1 Music Computer to be easily ported to the Sound Blaster. Voyetra will provide an optional VAPI Developer's Toolkit for software developers interested in supporting the Sound Blaster MIDI/FM features with the VAPI driver.

anyone interested in assisting and helping the cause
should be on the lookout for something called the "VAPI Developer's Toolkit" which is an SDK given out by Voyetra around 1990-1993 time frame for 3rd party hardware manufacturers to make their interface compatible with the voyetra software package "Sequencer Plus" - which is supposed to document the architecture of their driver and enable the companies to create their own Drivers, supporting the sequencer plus application platform

the reason to find it is to try to create the possibility of someone coding new drivers for midi hardware that can support the sequencer plus voyetra application on DOS. the hardware devices were traditionally mpu-401 compatible but with the design of the v22/v24s interfaces, voyetra departed from that design + instead chose to copy the architecture of the yamaha c1 music computer (laptop)

[chrisNova777]

http://raympoon.playgroundhk.com/bbs/midi7.htm

I couldn't find anything in the documentation on how to access the MIDI port. I'd like to write my own program. I phoned Creative Labs, and they suggested that I should buy the Development Kit ($100.00). I guess I have to wait until I have enough money to spend.

not sure if this would be the same development kit.. his comment seems to be sound blaster specific not voyetra specific.

[chrisNova777]

https://www.paia.com/talk/viewtopic.php?f=8&t=162
this post by Scott Paia is a repost of a message written by a Rick Massey
who expressed interest in the Vapi driver architecture, wanting to produce new drivers presumably for a new prototype midi interface that could support voyetra's DOS based sequencer

hes referencing a DIY midi interface kit that was produced by PAIA in the late 80s
http://www.oldschooldaw.com/forums/index.php?topic=4285.0

if anyone has any additional information please help by adding it here in this thread

Rick Massey wrote:
> > Scott,
> >
> > Over the years I've been fascinated by your company. I seriously
> > considered picking up a Strings N Things decades ago but lacked the
> > funds to get it, and have visited your site for many years to check
> > out what's available. Since I lost my sight back in 2003 I've been
> > less prone to picking up kit based gear as I can no longer put it
> > together myself, but I figured that at some point you'd make something
> > I couldn't live without and then I'd have to buy a kit and figure out
> > how to get someone else to assemble it for me.
> >
> > Then I saw your company mentioned today on a website, and it gave me
> > hope that you might be able to solve a long running quest of mine.
> >
> > I'm rather old school in some of my musical software uses, and that is
> > best shown by my choice of a sequencer -- Voyetra's Sequencer Plus
> > Gold 4.10. I use it because I know it well, it suits my needs, and I
> > like non-virtual interrupts for music, especially the system clock at
> > Interrupt 0. But I know that the V24 interfaces I currently use aren't
> > getting any younger, so I've been questing for any info I can find on
> > the VAPI standard Voyetra used to build the drivers for this program.
> > Voyetra has gotten so embedded in the world of CReative's sound cards
> > that they don't know anything about their older stuff. But since a web
> > site I found mentioned that PAIA also made a VAPI based interface, I
> > thought there was some possibility, however slight, that someone at
> > your company might have some information laying around about how to
> > code drivers for this interface specification.
> >
> > Right now my two V24sm interfaces work fine, but that won't always be
> > the case, and so if I can locate this specification I'll be able to
> > locate a more current interface that covers the bases I need covered
> > and I'll be able to keep chugging along using my sequencer of choice.
> >
> > Any assistance or leads you can provide on this would be greatly
> > appreciated.
> >
> > Sincerely,
> >
> > Rick Massey

[chrisNova777]

http://www.cs.cmu.edu/~rbd/doc/cmt/part1.html

This manual is a guide for users of the Carnegie Mellon University MIDI Toolkit, also known as CMT, a collection of software for experimental computer music using standard (MIDI) equipment.
This manual corresponds to CMT Versions 3.12 and higher.

http://www.cs.cmu.edu/~rbd/doc/cmt/part19.html
"Voyetra's VAPI protocol, which supports various devices including a MIDI interface that connects to a PC parallel port);

"If you use voyvapi, you can support regular MPU-401's as well by loading vapimpu.com in place of vapivp11.com.
See the Voyetra documentation for details."

not sure if this means the same developer toolkit referenced above

[chrisNova777]

http://www.mrspring.info/vbulletin/showthread.php?3174-Voyetra-Sequencer-amp-Hardware-PC-DOS-midi-Setup