A teletype selective call system.
Hugh Louis Shoemaker · Calhoun: The Naval Postgraduate School Institutional Archive (Naval Postgraduate School) · 1966
Current demands on communications facilities are necessitating conversion of existing single channel circuits to high speed, online encrypted, multiple channel circuits for military usage. Limited allotted frequencies and expensive cables require user sharing of most circuits, requiring selection methods to enable terminal equipment of the desired addressee. A selective call teletype device capable of operation at any commonly used speed, constructed with microcircuits, was designed and built to provide the terminal selection capability required in the multiple circuits. Small size, weight, and power requirements and the high reliability possible with microcircuits make a unit of this type attractive for conversion of existing systems as well as in the design of new equipment.