Re: "Co-Processor" Apple ?

[mjmahon@aol.com (Michael J. Mahon)]

Rob Jones wrote:

>robc638@startmail.ca (Robert C.) wrote in message
>news:<f86a396.0408061005.125a0b3d@posting.google.com>...

<snip>

>> Can two Apples be connected together so they can use each other's
>> processors? Or at least, can they be networked together?
>
>I am new to this group, but I have had my Apple II+ since it was
>bought new in September 1979 (I remember that date: I was begining my
>2cd year of High School). Since then I have moved up the line to a
>//e, then the original Mac, and upwards to the current Power Mac. This
>group has motivated me to dust off the II+ and //e. This particular
>thread on Networking the Apple is quite interesting. I know it would
>be quite easy to interface them and the Macs via the SSC in "Terminal"
>mode. However, to remain true to an Apple, would it not be possible to
>connect the "Cassette" jacks between the two? If I remember correctly
>from 25 years ago (I will need to dust off the Apple Reference Manual
>too), the Cassette "Out" and "In" can be accessed directly by PEEKing
>(and POKEing) at them.

This was recently discussed in this group.

The problem is that the cassette output is at "microphone" level, and
the level of the cassette input is "speaker" level, for direct connection
to the cassette decks of the day.

So, minimally, two audio amplifier is required to interface two Apples
using the cassette ports.

That will enable you to SAVE programs on one machine to the other
by first doing a LOAD on the other machine, and vice versa.

If you want to do anything more interesting,.you will have to write
software to control the ports to make something else happen.

Two peculiarities of the cassette ports that make them much less
interesting for general networking are:  1) the output can only be
"toggled", not set to a particular state (unless you examine its
state separately), and 2) the input is a capacitively coupled analog
input with some filtering, which impedes sending fast, digital signals.

All these issues caused me to prefer using an annunciator output
and a pushbutton input for NadaNet--it is both simpler and more
capable.

-michael

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