From: wrw2@cbnewsm.cb.att.com (w.r.wetzel)
Subject: Re: Voice Power equivalent for SPARC platform
Organization: AT&T
Distribution: usa
Date: Sun, 22 Nov 1992 23:19:20 GMT

A few comments on this topic.

There are at least a few cards available for the SPARC's for
audio I/O.  Many SPARC's come with an audio I/O facility already
built in.  Like Voice Power, this port transfers 8khz mu-law data
but it lacks a telephone line interface.  If you want hi-fi audio
quality you will have to go to one of the after market vendors.  The
one I hear mentioned a lot is Ariel.  They used to be in Highland
Park, N.J.  They have moved to another NJ location, sorry I don't know
where but a search through some of the SUN Journals should turn up
their address plus vendors for several other similar cards.  You may
even find one with a phone interface.

Let me mention one problem that several people have asked me about concerning
the interchange of mu-law data between Voice Power and SPARC's.  The 64k
mu-law data processed by Voice Power is bit-reversed and sense-reversed
from what might be called the 'sensible' mu-law expression.  The reason
we use it for Voice Power is that it is format used by the AT&T
digital signal processor (DSP) on the Voice Power card.  I have no idea why
the DSP uses this format, but it does.  (See an AT&T DSP manual for more
details).  So if you want to interchange Voice Power and SPARC mu-law
files you will have to write a simple program to flip the bits
(interchage 0<->7, 1<->6, 2<->5, and 3<->4), and invert their sense
(form the one's complement).  I do it in a little table lookup prog.

Now, on to some Voice Power history...

Voice Power was NOT developed for Audix.  In fact Audix was the farthest
thing from our (the developer's) minds when Voice Power was originally
conceived.  A brief history:

The original Voice Power card (long before the name Voice Power was
even used) was developed in the Summer of 1984.  It was an
XT bus card and we used an AT&T PC6300 (an Oliveti box) for testing.
I wrote the first version of the driver and voice editor for this card.
However, by Winter the 7300 was announced, we immediately changed
direction, and none of this ever made it out the door although some of
the software remains to this day in the driver and editor.

The design of the XT card was repackaged for the 7300 with a new bus interface
and physical design but otherwise essentially the same dsp, 8051,
and phone interface.  Our target application for this card was
'Office Automation', nothing else.  Hence, one of the first applications
written was the Answering Maching.  I never gave any thought to running
more than one card in the 7300, had no per-card arrays in the driver,
absolutely nothing that would support more than one card.

Pretty much as an experiment, one day I built three independent instances
of the driver by changing the names of the entry points and some
external variables slightly.  To our considerable suprise, the 7300
could run 3 cards simultaneously.  To make the point, we called in
our department head (the real promoter of VP at the time), had three
speakers set up, and played 'row, row, row your boat' a musical 'round'
adding an additional VP channel on each iteration of the round till
all three were speaking.   It was pretty impressive.

Eventually, I moved all card-specific data into an array and had one
driver that could support up to 7 cards using the expansion chassis.

That's the beginning.  Later we realized that we could not only answer
calls, but also transfer them, and the Automated Attendant was born.
That led the change in direction from 'Office' applications to real
'Telephony' applications.  Later yet, the 'Audix Voice Power' product
was developed (actually that was the last application we developed)
and that together with the Automated Attendant was the heart of the
'Integrated Solution' product that was an adjunct for the AT&T System
25 PBX switch.  Sold a lot of 3B1's, VP cards, and Sys 25's as a result.

There's a lot more to tell about the development of the VP1 and VP4
XT cards that followed the 3B1, but I will save that for another day.

Bill Wetzel
AT&T Bell Laboratories
Newsgroups: comp.sys.3b1