ETC was an outside test house in the 70s when customers didn't trust
vendors or needed outside help to support their internal QC..
Thanks. This is what I guessed, and means the IC's
have seen some third
party testing company. Some 2102 rams that I had bought "new" in tubes and
some from Godbout (S-100 memory cards) have the "ETC" stamp, so their
supplier had already gotten them this way, vs. direct from Intel.
Have seen the red enamel dots on IC packages as well, usually TTL.
-Dave
Other makrs were vendow dependant. The lead one mark was often color
coded for speed select (NEC RAM and CPU parts for example). Other uses
were batch marks or lot id's.
Allison