LSI ADM3A with an unusual keyboard

Ben bfranchuk at
Tue Jul 7 00:31:38 CDT 2009

Richard wrote:
> In article <FF6AB92D97A23A409701CDBF66F03FCD30CBA6F0 at 505fuji>,
>     Ian King <IanK at>  writes:
>> Oops, my bad: the ADM5 was hardwired as well. [...]
> After you mentioned that the ADM3A was discrete logic, I went to
> bitsavers and perused the maintenance manual.  The theory of operation
> section makes it quite clear that its all discrete logic doing the
> row/column counting and character decoding.  For some reason, I
> thought that the ADM3 was microprocessor based.  I guess I never
> really looked that carefully inside!  I have a number of terminal
> and graphics devices that are discrete logic and I find them
> interesting.
> I wonder how small an FPGA could be and still contain all the ADM3a
> discrete logic :-)
See Spare Time Gizmos for a very small dumb terminal. This is the cheap 
video cookbook
idea taken to the fullest. 2 1/2" x 4" PCB gives you every thing you 
need but a CASE and
a 9 volt wall wart. You don't get a ADM3A but a VT220 instead. How ever 
if you
want you can reprogram the CPU to emulate I guess almost any kind of 
basic terminal.

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