VINTAGE IBM SLT card w/ Inventory box. Military inv #5815986
SMS stands for Standard Modular System and was introduced in 1959 and continued in use into the early 1970s.
SMS had many digital logic circuit families, included many analog circuit types, and was also used for cable end connectors to plug into computers and their peripherals. It spanned discrete semiconductor technology, hybrid IC technology, monolithic IC technology, reed relay technology, systems/devices; making it probably one of the most versatile computer board designs ever developed.