04654818 is referenced by 100 patents and cites 15 patents.

A portable educational device that is adapted to be used in conjunction with a counter (12) having a display (14) and a keyboard (16) for input of data. A memory slot (18) or an alternate port (19) is provided on the computer (12) to receive the educational device (20). Educational device (20) contains a keypad (24) and a display (26) and operates independent of the computer (12). The educational device (20) includes a central processing unit (48), a Read Only Memory (42) and a Random Access Memory (44). A primary power source (54) supplies power to the educational device (20) during the operation thereof. A back-up power source (56) provides power to the Random Access Memory (44) to form a non-volatile memory for retention of data during periods of non-use. A connector (34) interfaces with the computer (12) to allow the computer (12) to address the Random Access Memory (44) to retrieve data stored therein and to store data at selected locations therein for use by the Central Processing Unit.

Title
Data processing device having memory selectively interfacing with computer
Application Number
6/562167
Publication Number
4654818
Application Date
December 16, 1983
Publication Date
March 31, 1987
Inventor
Lin C Wetterau Jr
Lubbock
TX, US
Agent
Melvin Sharp
Leo Heiting
William E Hiller
Assignee
Texas Instruments Incorporated
TX, US
IPC
G06F 15/20
G06F 15/16
G06F 13/00
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