The EIA assigns each manufacturer a three-digit code (there are some with one, two or four digits). The source dating code is an element of standardization that is administered by the Electronics Industries Association (EIA), formed in 1924. An Important Instrument Dating Breakthrough developed by Hans Moust (author, The Guild Guitar Book) Stamped on every potentiometer (volume and tone pots) is a six- or seven-digit source code that tells who made the pot, as well as the week and the year.
