Abstract: A programmable calculator utilizes an initialization key for setting all program variables, including array variables that are stored as part of a program in the calculator memory, to a predetermined initial value.

Abstract: An adaptable programmable calculator is provided by employing a modular read-write and read-only memory unit capable of being expanded to provide the calculator with additional program and data storage functions oriented towards the environment of the user, a central processing unit capable of performing both serial binary and parallel binary-coded-decimal arithmetic, and an input-output control unit capable of bidirectionally transferring information between the memory or central processing units and a number of input and output units. The memory, central processor, and input-output control units are controlled by a microprocessor included in the central processing unit. Also the calculator may be operated manually by the user from an alphanumeric keyboard input unit or automatically by a program stored within the memory unit to perform calculations and provide an output indication of the results thereof. It may also be employed to load programs into the memory unit from the keyboard input unit.

Abstract: An adaptable programmable calculator is provided by employing a modular read-write and read-only memory unit capable of being expanded to provide the calculator with additional program and data storage functions oriented towards the environment of the user, a central processing unit capable of performing both serial binary and parallel binary-coded-decimal arithmetic, and an input-output control unit capable of bidirectionally transferring information between the memory or central processing units and a number of input and output units. The memory, central processor, and input-output control units are controlled by a microprocessor included in the central processing unit.

Abstract: An adaptable calculator is provided by employing five MOS/LSI circuits interconnected by a multiple line bus system. They include (1) a read-only memory circuit group; (2) a control and timing circuit; (3) an arithmetic and register circuit; (4) a data storage circuit; and (5) an input/output (I/O) circuit. Input and output units include a keyboard input unit and an 18-column output printer unit for printing intermediate results of calculations, entered data, arithmetic operators, and diagnostic notes. The keyboard input unit includes a PERCENT key that may be employed in combination with any of four arithmetic operator keys. The calculator may be operated manually by the user from the keyboard input unit or automatically by a program written in user-level language and stored in a plug-in read-only memory unit (ROM), a plug-in programmable read-only memory unit (PROM) or a read/write memory unit associated with a plug-in magnetic card reading and recording unit.

Abstract: An adaptable calculator is provided by employing five MOS/LSI circuits interconnected by a multiple line bus system. They include (1) a read-only memory circuit group; (2) a control and timing circuit; (3) an arithmetic and register circuit; (4) a data storage circuit; and (5) an input/output (I/O) circuit.Input and output units include a keyboard input unit and an 18-column output printer unit. An optional LED display unit may be plugged into the calculator mainframe. The keyboard input unit includes an AUTO DECIMAL POINT key for selecting an automatic decimal point mode of calculator operation in which the calculator automatically places the decimal point at a specified location in all entered data. Thus, the operator need not manually enter the decimal point in entered data. The calculator may be operated manually by the user from the keyboard input unit or automatically by a program stored in the calculator memory.

Abstract: An adaptable programmable calculator is provided by employing a modular read-write and read-only memory unit capable of being expanded to provide the calculator with additional program and data storage functions oriented towards the environment of the user, a central processing unit capable of performing both serial binary and parallel binary-coded-decimal arithmetic, and an input-output control unit capable of bidirectionally transferring information between the memory or central processing units and a number of input and output units. The memory, central processor, and input-output control units are controlled by a microprocessor included in the central processing unit.

Abstract: An adaptable programmable calculator is provided by employing a modular read-write and read-only memory unit capable of being expanded to provide the calculator with additional program and data storage functions oriented towards the environment of the user, a central processing unit capable of performing both serial binary and parallel binary-coded-decimal arithmetic, and an input-output control unit capable of bidirectionally transferring information between the memory or central processing units and a number of input and output units. The memory, central processor, and input-output control units are controlled by a microprocessor included in the central processing unit.

Abstract: An adaptable programmable calculator is provided by employing a modular read-write and read-only memory unit capable of being expanded to provide the calculator with additional program and data storage functions oriented towards the environment of the user, a central processing unit capable of performing both serial binary and parallel binary-coded-decimal arithmetic, and an input-output control unit capable of bidirectionally transferring information between the memory or central processing units and a number of input and output units. The memory, central processor, and input-output control units are controlled by a microprocessor included in the central processing unit.

Abstract: A method and apparatus are provided for decoding digital information stored on magnetic tape. The "zero" and "one" bits are represented respectively on the tape by "short" and "long" distances between flux transitions. Decoding is accomplished by measuring the time between flux transitions and comparing that time with a reference time. Times longer than the reference time are decoded as "ones" while time intervals shorter than the reference time are decoded as "zeroes." To make the decoding independent of variations in tape speed the reference time is variable and in particular is made dependent on the tape speed. This is accomplished by updating the reference time based on previous "long" and "short" intervals between flux transitions. Circuitry is provided in which the various times are converted to voltages which are appropriately sampled and updated in accordance with the tape speed.

Abstract: An adaptable calculator is provided by employing five MOS/LSI circuits interconnected by a multiple line bus system.