Re: Is this an Apple ][ clone?

[et472@FreeNet.Carleton.CA (Michael Black)]

Mitchell Spector (mitch2gs@hotmail.com) writes:

>     There is an small circuit card that plugs into the standard 
> 16-pin keyboard connector and has a DIN-5 connector for
> the PC/XT keyboard (incidentally, I remember trying a PC
> keyboard on it, or its keyboard on a real PC--they're definitely
> not compatible). 
	
I don't know whether it was the same clone, but I was given one that certainly
was on the same level.  It had an "IBM" keyboard and that little serial
to parallel board that plugged into where the regular keyboard went.

But, when it wsa given to me, it came with a ROM that could be put back
in to turn it back into an "IBM" keyboard.

I don't think I ever tried it, and I dont' think I still have it.

But it made sense.  There is very little circuitry in those keyboards,
despite them being quite a bit fancier than a regular Apple keyboard. Not
much beyond a CPU and the ROM and a few interface ICs.  Make the effort
to figure out what's there, write the code to be Apple compatible, and
it likely was far less work than trying to have serial keyboards
manufactured from scratch.

That little interface board was simple because all it had to do was
collect 8 bits of serial, and then output it in parallel, with something
to indicate to the Apple that the "key had been pressed".

But of course, if the "IBM" keyboard had remained "IBM compatible" that
board could not be so simple, since the "IBM Keyboard" puts out scan
codes that can't easily be converted to ASCII and indicate a key up
by sending a different scan code.

In order for the little converter board to work, it needed to see
normal ascii at its input.  Hence that converter could be used with
any keyboard that put out serial ASCII, including a Teletype keyboard
if the voltage levels were interfaced properly.

   Michael