duocase

Before the introduction of the IBM 1050, printing terminals had been limited to single case capability. But the use of an electric typewriter on the 1050 would give the capability of duocase printing—capital letters and small letters. This duocase capability was held to be a very significant marketing factor.

1980, Charles E. McKenzie, “The Size and Structure of PTTC” (chapter 6), in Coded Character Sets: History and Development (The Systems Programming Series), Reading, Mass.: Addison-Wesley Publishing Company, →ISBN, page 106