Abstract: A programmable calculator having modular read-write and read-only memory units, a central processing unit, a keyboard input unit, and an output display unit includes keys on the keyboard input unit for enabling the user to efficiently and effectively edit programs stored in the read-write memory unit.

Abstract: A programmable calculator having modular read-write and read-only memory units, a central processing unit, a keyboard input unit, and an output display unit, includes keys on the keyboard input unit for performing angular measurement unit conversion.

Abstract: A modular read-write and read-only memory unit capable of employing both direct and indirect decimal and symbolic addressing, a central processing unit capable of performing both serial binary and parallel binary-coded-decimal direct and indirect memory register arithmetic, and an input-output control unit capable of bidirectionally transferring information between the central processing unit and a number of input and output units are controlled by a microprocessor included in the central processing unit. The input and output units include a keyboard input unit with a section capable of being defined by plug-in read-only memory modules and stored programs added by the user, a magnetic card reading and recording unit capable of bidirectionally transferring information between an external magnetic card and the calculator, and a solid state output display unit capable of displaying three lines of numeric information.

Abstract: A modular read-write and read-only memory unit capable of employing both direct and indirect decimal and symbolic addressing, a central processing unit capable of performing both serial binary and parallel binary-coded-decimal direct and indirect memory register arithmetic, and an input-output control unit capable of bidirectionally transferring information between the central processing unit and a number of input and output units are controlled by a microprocessor included in the central processing unit. The input and output units include a keyboard input unit, a magnetic card reading and recording unit capable of bidirectionally transferring information between an external magnetic card and the read-write memory unit, and a solid state output display unit capable of displaying three lines of numeric information.

Abstract: The modular read-write and read-only memory, central processing, input-output control keyboard input and output printer units of the calculator described herein provide an adaptable programmable calculator that may be operated manually by the user from the keyboard input unit or automatically by a program stored in memory. Programs may be loaded directly into memory from the keyboard and either data or programs may be separately transferred bi-directionally between the memory unit and an external magnetic card. Programs stored in the memory unit may be edited and key-coded logs, program lists, labels, and messages may be printed by the output printer unit by specifying one of several modes of the calculator. In one of the modes, the printer will print a log comprising a listing of a key code for each key actuated, of nearly all programmable operations performed from the keyboard.

Abstract: A modular read-write and read-only memory unit capable of employing both direct and indirect decimal and symbolic addressing, a central processing unit capable of performing both serial binary and parallel binary-coded-decimal direct and indirect memory register arithmetic, and an input-output control unit capable of bidirectionally transferring information between the central processing unit a number of input and output units are controlled by a microprocessor included in the central processing unit. The input and output units include a keyboard input unit with a section capable of being defined by plug-in read-only memory modules and stored programs added by the user, a magnetic card reading and recording unit capable of bidirectionally transferring information between an external magnetic card and the calculator, and a solid state output display unit capable of displaying three lines of numeric information.