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Re: Apple II keyboard encoder - need specs for optional right-angle slide switch



On Tuesday, May 8, 2012 11:49:51 PM UTC-4, Ralph wrote:
> I'm trying to track down details on adding a keyswitch to the Apple II

I'm like a dog with a bone with this, not ready to let go yet.

Had some free time this evening and tracked down the Creative Computing issues I lacked ... still haven't found the specific article which mentioned the switch type, but the "Apple Cart" columns don't mention this (Jan '80 through Dec of '83 were checked, though I couldn't find April '83, May '83, or June '83

I've attached the post about the "Apple ][ keyboard encoder", the cctalk archives seem to stop at 2005, though some earlier years are still in Google's cache.

I may have to track down folks who wrote for the magazine in that era, just to see what they might recall....

Cheers,

- Ralph

-- cctalk article on Apple ][ keyboard encoder (from Google cache) --

Sam Ismail dastar at ncal.verio.com
Mon Sep 14 18:10:32 CDT 1998

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On Mon, 14 Sep 1998, Tony Duell wrote:

> There are 2 unused positions on this board. One is marked S2, and seems 
> to be for a DPDT switch. There are X-pads to cut (I guess) when you 
> install this switch. 

I found the perfect book to answer this question over the weekend.  Its
called _The Apple II Circuit Description_ by Winston D. Gayler.  It
includes in-depth technical descriptions of the Apple II and detailed
fold-out schematics of every major subsystem in the Apple II, including
the CPU, the bus pinouts, the keyboard, etc.

This should answer your question:

"Quad-mode operation--B6 is a quad-mode encoder.  This means each key can
generate up to four different characters as a function of the SHIFT and
CTRL keys.

"Lowercase--there are two bow ties on the board with the ICs [the encoder 
board].  They may be cut as a user option.  The circuit is then restored
by adding switch S2.  In the normal position of S2, the circuit functions
as previously described [ie. normal Apple II keyboard encoding].  When S2
is operated, output bits 9 and 8 are substituted for bits 5 and 6.
Encoder B6 has been programmed with ASCII lowercase letters.  This
substitution of bits will make the lowercase letters available.
Lowercase operation is as follows: with the shift key not depressed,
pressing any letter key will output lowercase.  With the shift key
pressed, pressing any letter key will output uppercase.

Numeric pad--As a user option, a nine-pin connector may be installed on
the keyboard at J2.  Then J2 can be extended to a numeric pad."

Let me know if you have any more specific questions.  This book is
excellent.

Sam                               Alternate e-mail: dastar at siconic.com
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