[Blindapple] running Textalker conditionally

[Kyle]

Using some clever chr$(7)chr$(7) pairs of beeps for verification, and
getting a little help from Google Goggles, I have found that

* PEEK(54) is always 189
* PEEK(55) is always 158
* PEEK(56) is always 129
* PEEK(57) is always 158

I get these values whether Textalker is running or not. This is using
the standard Applesoft in ROM via 2 DOS 3.3 compatible disks, one with
my DOS Bossed Pronto-DOS and the other with Apple's DOS3.3 as found on
EGAMES.DSK. On the other hand, the Talking Writer test as found on line
10000 of its HELLO program appears to work. The value of PEEK(43603) is
240 when Textalker is not running, and either 124 if a newer version of
Textalker i.e. 3.1.2 or 3.1.3 is running or 0 if textalker.blind version
1.3 is running. This has been tested both on my DOS Bossed version of
Pronto-DOS and on Apple DOS3.3 as found on EGAMES.DSK.

So the only thing left to do is to attempt to iterate through each slot
2 through 5, apparently these are the only legal slots for an Echo, and
to determine whether or not an Echo is connected to any one of these
either before checking whether or not Textalker is running or just after
finding out that PEEK(43603) is 240, which is actually probably the best
time to run such a test, probably from within a GOSUB. The example code
I found still requires that an already existing binary module be loaded
into RAM before I can call the subroutine from within Applesoft, so I'm
essentially back where I started, as I want to do the entire detection
routine from Applesoft as part of an existing HELLO program. I basically
just need documentation on how to detect whether a card is plugged into
a specific slot, and I should be able to take it from there.
~Kyle
http://kyle.tk/
-- 
"Kyle? ... She calls her cake, Kyle?"
Out of This World, season 2 episode 21 - "The Amazing Evie"