Who first proposed the distinctive shapes and the rectangular shape labels?
What is the consideration behind the shapes and the labels?
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1 Answer
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The "distinctive shapes" specified in IEEE Std 91/91a-1991 derive from MIL-STD-806 Graphical Symbols for Logic Diagrams, which was originally a US Air Force standard. This in turn was based on a 1960 paper sponsored by the American Institute of Electrical Engineers and American Society of Mechanical Engineers which begins:
"Because the development of acceptable logic symbols has not kept pace with the use of electronic data-processing equipment by both the military and industry, a serious state of emergency now exists. This was the basis for calling together on September 8, 1960, individuals representing the many groups working in this area to consider the desirability of forming a task group under ASA Sectional Committee Y32 to propose a solution." (The Magazine of Standards, Volumes 30-31)
The foreword to IEEE Std 91-1984 gives some more background, but still doesn't describe the earliest evolution of the symbols:
"It is the latest step in a program that began in 1956 within the IEEE to develop a comprehensive single standard, consistent with ongoing developments in technology and logic symbology, from several ad hoc, industry, military, and international standards. In 1960, an ad hoc group on logic diagram graphic symbols was formed within the American National Standards Institute in order to develop a draft American Standard. In 1961, this committee became a permanent subcommittee, Y32.14, of the Graphic Symbols Committee, Y32, under the cosecretariat of ASME and IEEE."
The "rectangular shapes", meanwhile, are based on a gradual evolution of standards developed in the US (and to a lesser extent the UK) during the 60's, 70's and 80's, starting with IEE Std 91-1962 and IEC 117-15 of 1972, which codified some of the basic ideas, and continuing with ANSI Y32.14-1973, BS 3939-1977, IEC 617-12 of 1983 and IEEE Std 91-1984.
It's worth noting that there is also a third style of symbols still occasionally used in Europe and probably German in origin. This is codified in DIN 40700: see for example this table on German Wikipedia.
