I can't really take credit for this idea, as somebody suggested it to me
a while ago.  But anyway, here it is...

The Apple II has a mainly unused set of routines in the monitor which
encode data as audio (sending it out the cassette output port) and which
can decode audio into data (coming from the cassette in port).  If you
already knew that, I do apologize for wasting ten seconds of your life.
At some point Apple took the jacks out, but I think that at least some
//es have them, and everything prior to that does for sure.

So I've fiddled with STM's speaker module to respond to the cassette out
soft switch as well as the speaker out; by running a cable from the
mac's audio out (1/8") to the Apple II's cassette input (RCA jack), you
can move stuff from STM to the real II.  This can be handy for, say,
moving disk transfer programs that you've downloaded, or whatever.

In case your original manuals are long lost, here's how you do it:

To transfer applesoft programs, type 'LOAD' on the receiving end, then
'SAVE' on STM.  A few seconds will go by, then a beep, then the transfer
proceeds, then another beep when it's done.

To move data from the monitor, type '<start>.<end>R' on the receiving
machine, then '<start>.<end>.W' on STM.

On my setup, at least, the volume setting on STM has to be 'high'. Also,
any hiccup in the audio flow will mess things up (fortunately, the
routines do checksums).  So if you have a slow machine, close windows
like the speed readout, profile window, and 6502 monitor window.

The fly in the ointment is that whenever STM's internal clock rolls over
(I don't remember how often..15 to 20 minutes maybe), there's a little
hiccup in the audio which will also foul a transfer.  You can tell when
the clock rolls over by a message in the messages window ("time
wrapped").

You can get the new speaker module from cassandra.ucr.edu in
pub/apple2/STM/cassettespeaker.sit.bin

And that's that.

    Kevin