Old Calculator Web Museum Documentation Archive
Friden "Four Counter" EC-132 MDD (Master Design Documentation) Computer Printout, June, 1965
Friden EC-132 "Four Counter" MDD Computer Printout (June, 1965)
This document is an internal Friden "Master Design Document" (MDD) that describes the entire design of the calculator. It documents the signals used, logic gate connectivity, and component connectivity and location on the circuit boards for the Four Counter EC-132 (Serial Number <3902). This document has not been decoded in terms of how to read/interpret the content. It is presented here in hopes that it will solicit discussion and perhaps lead to the document being decoded. If you have comments or questions about this document, please contact the curator of the museum. Section I (glossary) appears to define all of the signal names used in the machine. Section II (logic schematic), appears to define the machine in terms of its logic elements (gates, inverters, flip flops), and how the logic elements are interconnected. Section III (construction file) appears to define the actual component netlist and cicuit board component layout.
The document also includes schematics for various subsections of the calculator, as well circuit board layouts, with all components identified by a number that refers back to the Card Map Legend page to specify the component value or part number.
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