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US5450078A
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Membrane computer keyboard and method
Assignee: Kurzweil Educational Systems Inc
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Filing: 1992-10-08
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Granted: 1995-09-12
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Expires: 2012-10-08
Abstract
Abstract A computer keyboard having an output port through which scan codes are directed to a computer CPU over a cable, the keyboard of the kind having a touch activated membrane switch onto which one of a plurality of key layout overlays can be installed. Each of a plurality of different stored data tables is operable when selected to determine the particular scan code that is directed through the keyboard output port over the cable in response to a membrane switch being activated. Each overlay being coded in a way that can be read by an overlay code identification device which automatically operates in response to a coded key layout overlay being installed onto the keyboard to read the overlay code, which is then used by a data table selector to select a particular data table for use with the installed overlay.
Inventors
- 👤 Michael J. Silva
- 👤 Brian P. Lee
- 👤 Arjan S. Khalsa
- 👤 David C. Schmitt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:06
CPC Classifications
H; H01; H01H; H01H13/00; H01H13/70; H01H13/702; G; G06; G06F; G06F3/00; G06F3/01; G06F3/02; G06F3/0202; G06F3/0224; G06F3/023; G06F3/0238; G06F3/03; G06F3/033; G06F3/0354; G06F3/03547; G06F3/039; G06F3/0393; G06F3/048; G06F3/0487; G06F3/0488; G06F3/04886; G06K; G06K7/00; G06K7/10; G06K7/14; H01H2219/00; H01H2219/002; H01H2219/026
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
332 words
In a computer keyboard having an on-board microprocessor and ROM, an output port through which scan codes are directed to a computer CPU over a cable, wherein the cable is connected at its keyboard end to the output port of the keyboard by a keyboard connector plug and at its CPU end to the CPU keyboard input port by a CPU connector plug compatible with a particular CPU and the keyboard is of the type having a plurality of touch activated switches under a membrane onto which one of a plurality of different key layout overlays can be installed and wherein the microprocessor generates one of several possible internal signals in response to activation of a touch activated switch, the improvement comprising: a plurality of overlay mapping data tables stored in the on-board ROM wherein each overlay mapping data table has a plurality of levels and is associated with a particular key layout overlay; an overlay identification code on each key layout overlay, an overlay identification code detector on the keyboard responsive to a key layout overlay being installed onto the keyboard to detect said overlay identification code on the installed key layout overlay and generate a signal representative of such detected code; an overlay mapping data table selector in the microprocessor responsive to the signal generated by said overlay identification code detector to select a particular overlay mapping data table for use with the installed key mapping overlay; a CPU code on the keyboard connector plug identifying the particular CPU with which the CPU connector plug on the same cable is compatible; a CPU code detector on the keyboard for detecting said CPU code on a keyboard connector plug plugged into the keyboard and generating a CPU identifying signal; and an overlay mapping data table level selector in the microprocessor responsive to the signal generated by said CPU code detector to select a particular overlay mapping data table level for use with the CPU connected to the keyboard by the cable.
Claim 2
Dependent Claim
332 words
In a computer keyboard having an on-board microprocessor and ROM, an output port through which scan codes are directed to a computer CPU over a cable, wherein the cable is connected at its keyboard end to the output port of the keyboard by a keyboard connector plug and at its CPU end to the CPU keyboard input port by a CPU connector plug compatible with a particular CPU and the keyboard is of the type having a plurality of touch activated switches under a membrane onto which one of a plurality of different key layout overlays can be installed and wherein the microprocessor generates one of several possible internal signals in response to activation of a touch activated switch, the improvement comprising: a plurality of overlay mapping data tables stored in the on-board ROM wherein each overlay mapping data table has a plurality of levels and is associated with a particular key layout overlay; an overlay identification code on each key layout overlay, an overlay identification code detector on the keyboard responsive to a key layout overlay being installed onto the keyboard to detect said overlay identification code on the installed key layout overlay and generate a signal representative of such detected code; an overlay mapping data table selector in the microprocessor responsive to the signal generated by said overlay identification code detector to select a particular overlay mapping data table for use with the installed key mapping overlay; a CPU code on the keyboard connector plug identifying the particular CPU with which the CPU connector plug on the same cable is compatible; a CPU code detector on the keyboard for detecting said CPU code on a keyboard connector plug plugged into the keyboard and generating a CPU identifying signal; and an overlay mapping data table level selector in the microprocessor responsive to the signal generated by said CPU code detector to select a particular overlay mapping data table level for use with the CPU connected to the keyboard by the cable.
Claim 3
Dependent Claim
65 words
The invention of claim 1 further comprising: a plurality of internal code translation tables stored in the ROM for translating internal code to scan code; an internal code translation table selector in the microprocessor responsive to the signal generated by said CPU code detector to select a particular stored internal code translation table for translating internal code to scan code understandable by the detected CPU.
Claim 4
Dependent Claim
25 words
The invention of claim 2 wherein said CPU code is a plurality of plug connector pins selectively electrically connectable to one another in various combinations.
Claim 5
Dependent Claim
27 words
The invention of claim 3 wherein said CPU code detector is operable to ascertain the connection combination of said plug connector pins at the keyboard output port.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-09-11 | 1999-03-13 | 1999-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-09-11 | 2003-03-13 | 2003-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-09-11 | 2007-03-13 | 2007-09-12 | $7700.00 | Window Closed / Lapsed |