Early Apple Keyboards

Apple 1

Apple 1 computers did not come with a keyboard.  The operations manual did specify what could be used: "Any ASCII encoded keyboard, with positive DATA outputs, interfaces directly with the Apple system via a "DIP" connector."  The Datanetics keyboard was probably pressed into service with an Apple 1 more frequently than any other kind.  In fact there is evidence that Steve Jobs of Apple recommended this keyboard.

Datanetics Rev B
Photo courtesy of John Calande -  http://apple1computer.blogspot.com/

The image above is a Datanetics rev B.  It used a National MM5740/AAE decoder chip.  The data book and app. notes for this part can be downloaded  from here.
More technical information about this keyboard can be found on my Datanetics page.  This keyboard was apparently being or completed manufacturing on May 28,1976 and based on the markings, could be serial #10.  I believe that the DC stands for Datanetics Corporation.

manufacturing markings 

The Datanetics Corporation made their own keyswitches which were patented (#3777090).  The patent can be found here and includes a detailed description of the operation of this keyswitch.  Here is an image of the keyswitch.  Identical keyswitches exist with a straight stem, but it is not known what products, if any, they were used in.
datanetics corp. patented keyswitch

The Datanetics keyboard had a unique feature that allowed the user to wire 4 "blank" keys to any decoded character desired.  This was done by connecting the row and column using the matrix on the top and bottom of the upper left side of the PCB.  The holes in this matrix were not plated, so  there was no connection between top and bottom copper layers unless the user ran a wire through the hole.   What follows is a CAD image of a reproduction I'm working on, showing how the matrix was connected to keys 27, 41, 54 and 56 (the blank keys).  The blue traces are on the back layer and lead to the key switches.  The red traces are on the front of the PCB and lead to the keyboard encoder chip.

datanetics matrix

These blank keys were also connected to the edge connector on the upper right side of the keyboard so other user functions could be implemented.

The Apple 1 had two keyboard controlled functions that were a bit unusual.  First was the fact that the prom monitor used underscore as the backspace/rubout feature.  The other was a clear screen function that required the clear screen input signal to be pulled up to +5 volts to clear the screan.  The clear screen function could be implemented on datanetics keyboards by properly connecting a blank key from the edge connector to the 16 pin DIP port.  My current understanding is that the underscore is not implemented in the MM5740/AAE chip, so there was no way to use the Apple 1 monitor backspace feature with this keyboard.

rev D datanetics
Photo courtesy of Cliff & Dick Huston from EarlyApple Ebay Auction, March 2010

These keyboards evolved rather rapidly and later versions had some changes, including a solder mask.  Here is an image of a rev D.  Note the keycap shaped power indicator light.    Other changes include bigger shift and return keys and arrows instead of rubout key.  This keyboard is very similar to the first Apple II keyboard seen in next section.

Remember that other manufacturers keyboards were frequently used with the Apple 1.

Apple II

Apple II's initially came either as motherboards without keyboard, case or power supply or as complete computers.  If you purchased a motherboard, you had to find your own keyboard.  Most parallel ASCII encoded keyboards available at the time could be interfaced to an Apple II motherboard, including the Datanetics.

First Version

first A2 keyboard

The first keyboard supplied with the Apple II is shown above.  It was apparently made by Datanetics for Apple, as the keyswitches are Datanetics patented keyswitches identical to those used on the earlier Datanetics keyboards.  However there is no manufacturer identified on the board itself to prove that Datanetics actually made it. The layout is very similar to the rev D datanetics show above.  This keyboard came with Apple II serial number 2672.  Also the manufacturing date and serial stamps are similar to the Rev B Datanetics.  This one was stamped March 2, 1978 and has an apparent serial number of 2779.

keyboard version 1 markings

This keyboard also used the MM5740/AAE keyboard encoder. This keyboard had an  edge conector, which had a different pinout from the datanetics edge connector.  This edge connector is rarely used on an Apple II.   When the top of the computer case was removed, the top edge of the keyboard extetended a bit into the opening.  The combination of this extension,  the edge connector and the MM5740/AAE led to serious problem with static charges frying the MM5740 encoder on these early machines.

Second Version

second version

This version was introduced roughly around serial number 3000 of the Apple II production.  This version is electically identical to the first version.  However the MM5740 was moved and the exposed edge connector was removed.  This is an apparent attempt to eliminate the problem with static charges destroying decoders.    This change eliminated the extension that extends into the area of the enclosure that is exposed when the cover is removed.

This example was dated Jul 20, 1979, right around the beginning of A2 plus production.  The keyboard came with A2 plus serial number 2737 which I purchased off of ebay.  The interesting thing about it is the dome power light.  I've seen earlier serial numbered A2 plus systems listed on ebay that have a square power light.  I suspect the serial number is 29876, but it is hard to know if this is a correct assumption and when the numbering started.

second version markings

Version 2 Keyboard Production Changes

I have a later copy of the second version keyboard and it is different from the first in several ways.

Power Light Change

Apparently during production of this second version keyboard, the power light was switched to a raised square light.  I have speculated that this indicator was changed because some people might have confused this indicator with an actual power switch.  The dome light is on the early keyboard and the square light is on the later one.

dome power lightraised square power light

The image below shows the manufacturing markings on this later production copy.  It seems that it was stamped by manufacturing on Nov  29, 1979 and had a possible serial number of 148164.

version 2 - later markings

Besides the power light, another difference between these versions is the solder mask, which is brown on the second version.  These two boards were clearly made by different PCB fab houses.  Electical function seem identical.
earlier versionversion 2 - later date

Apple II and Apple II plus System Differences

There was significant overlap in production time of the Apple II and Apple II plus.  During this overlap, the only difference between the machines was the programs loaded into the ROMs.  The very first Apple II plus systems have the second version keyboard.

End of the MM5740/AAE Encoder

With the next version keyboard, the MM57040/AAE encoder was replaced by a separate plug in encoder that contained a SMC KR3600 encoder.

First RFI Version

This keyboard is the first version that was RFI compliant.

RFI keyboard

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