Alpha Syntauri keyboard interface

[mjmahon@aol.com (Michael J. Mahon)]

I recently acquired a 5-octave Alpha Syntauri velocity-sensing
keyboard.  This is, of course, pre-MIDI--designed to be used
with their Apple II synthesis system.

As you probably guessed, the keyboard came without its
interface card.  The keyboard has a DB-25M connector and
was cabled directly to a proprietary interface card in an Apple
slot.

Does anyone have information about this interface?

The keyboard logic is pretty straightforward, with a 1:16 demux
driving a 16x8 switch matrix.  (Each keyswitch is a SPDT switch
with separate sensing of "key up" and "key down" conditions,
permitting keypress velocity to be computed by counting the
time between "key not up" and "key down".)

The keyboard could be used with direct polling by the Apple
and a relatively simple buffer interface.  But since the processor
has a few other things to do during synthesis (!), I'm guessing
that the interface contained other means for doing the timing.

-michael

 Email:  mjmahon@aol.com
 Home page:  http://members.aol.com/MJMahon/