Extendable modular decoder unit - for selection of a terminal out of a number of terminals

摘要

Identically constructed subunits consists of a superoridnate unit and a number of other equal in rank decoder units selected by a first address signal applied to the first decoder unit; the first address signal is logically linked with specified selection signals, and the result marks one of the subunits as the selected subunit which activates one of the 128 terminals in accordance with a second address signal; the first address signal is partly added modulo 2 to the specified selection signals; this addition is carried out by an EXCLUSIVE-OR circuit.