[Blindapple] Emulating Echo

[Jayson Smith]

Hi,
Actually, this might be quite tricky.  Because what Textalker is going to
send to the slot where the Echo is located certainly won't be the actual
text to be spoken, and probably not even the phonemic representation.
What's probably being sent is some form of very low level signaling to tell
the LPC chip what noises to make when.  If you remember, on a real Apple,
whatever the Apple does comes to a dead hault when the Echo is speaking.
This is probably because Textalker is taking up the processor time by
converting the printed words into phonemes, then converting the phonemes
into the low level signals for the LPC chip, then sending those signals to
the card itself.
Jayson.

----- Original Message -----
From: "Tony Baechler" <tony at baechler.net>
To: "Blind Apple Discussions" <blindapple at jaybird.no-ip.info>
Sent: Thursday, July 28, 2005 10:08 AM
Subject: [Blindapple] Emulating Echo


> Hi.  Is there a way of finding out what it sends to the slot to detect
> whether there is a real Echo or not?  I tried various tricks to find out
> but as yet have been unsuccessful.  Obviously I know it sends something
> because that is how the Doubletalk knows when to switch.  Is there a way
to
> patch Textalker to only look for a card in slot 1?  I think I am
reasonably
> close to making A2 simulate an Echo but I need a way to trick Textalker
> into sending to slot 1 even though there is no Echo there.  I know there
is
> a way to do this with the older versions, but what about the 3.1 APH
> series?  I believe that even though we can't really ever use a real Echo
> under emulation, it can be simulated fairly easily.  I played with this a
> little and looked at the C source and it looks simple enough.  Aalas, if
A2
> only emulated sound!  However, if I can get something going under A2, it
> might be possible to make it work with a better emulator.  Please, if you
> know any C programmers, contact me!  This would take a good programmer
very
> little time to do since I think I know what needs to be changed.
>
> For those interested, all this stuff is in jump.c and vidout.c.  The
jump.c
> opens a2.printlog if someone activates slot 1.  The vidout.c is obviously
> for video output and opens a2.log if running under Linux.  Both look
simple
> enough and I think they could be easily modified.  The only other thing I
> might need is a dump of the Echo ROM, which I think is in the c400 range
> for slot 4 from within the monitor.  I could very well have no idea what
> I'm talking about, but I would like to try more experiments.  My initial
> attempt did work reasonably well, but not quite good enough.
>
> If anyone else wants to try this, do the following from DOS.  First,
unload
> the screen reader and the synth drivers.  I use Vocal-Eyes so I do "ve /u"
> and I use the DEC-Talk Express so I do "dtexp /u."  Then, assuming you are
> in com1, do the following:
>
> a2 >com1 disk.dsk
>
> Replace disk.dsk with a bootable disk.  Speech should come directly out
the
> synthesizer.  Try cataloging to make sure.  If something bombs, hit
Control
> C, "q" and enter.  If nothing happens, repeat.  Exit the DOS window or
> somehow reload your screen reader.  This isn't perfect since you don't get
> review mode at all and it doesn't always speak right away as it should,
but
> it is a good start.  I believe that it can be done, maybe easier than I
> thought.  Criticisms are welcome.
>
> Oh, I made a mistake about A2.  It is not licensed under the GPL.  Make
> sure to read the comments in the source before changing anything.  It
> allows free copying and distribution, but it doesn't comply with the GPL
so
> may not be considered "free" by some people.  I'm not personally bothered
> by it, but others might be.
>
> At 08:21 PM 7/27/2005 -0400, you wrote:
> >Actually my Doubletalk can be freely switched between Echo and Doubletalk
> >mode.  To use Doubletalk, in Basic you just type pr#X where X is the slot
> >where the card is installed.  Then the card emulates a printer in that
slot,
> >so anything sent to it will be spoken with the Doubletalk voice.  To use
the
> >Echo emulation, which isn't perfect but does get the job done, you must
load
> >the Textalker software as if you had a real Echo installed.
> >Jayson.
>
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