[Blindapple] Emulating Echo

[Tony Baechler]

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.