Cordless keyboard

• US 5,081,628 A
• Filed: 09/01/1989
• Issued: 01/14/1992
• Est. Priority Date: 09/17/1988
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Hirano, Yuji, Maekawa, Hitoshi
• Primary Examiner(s): ATKINSON, CHARLES
• Application Number:
  US07/401,802
• Time in Patent Office: 865 Days
• Field of Search: 371/34, 455/69, 455/603
• US Class Current: 714/750
• CPC Class Codes: G06F 11/1497 Details of time redundant execution on a single processing unit
• CPC Class Codes: G06F 3/0231 Cordless keyboards
• CPC Class Codes: H04L 1/14 in which the signals are sent back to the transmitter to be checked ; echo systems

Abstract

Signals are transmitted using light or the like in a cordless manner between a keyboard and a controller related thereto. The keyboard transmits a signal that indicates a keycode corresponding to a key to the controller in a cordless manner, and the controller sends the keycode signal back to the keyboard. The keyboard compares the transmitted keycode with the received keycode to check whether the keycode signal is correctly transmitted to the controller. When the communication is to be carried out between a plurality of keyboards and the related controllers, a device code specific to the keyboard is attached to the keycode such that the individual keyboards can be identified.

Claims

1. A cordless keyboard in which signals are transmitted in a cordless manner between a keyboard and a controller related to said keyboard, wherein said controller comprises:

receiving means which receives from said keyboard a signal that represents a keycode;

sending means which sends back to said keyboard the signal that is received and that represents said keycode; and

said controller includes means responsive to a next keycode received within a fixed period of time after said keycode has been received for discarding the keycode and sending back said next keycode.

2. A cordless keyboard according to claim 1, wherien said receiving means of said controller receives said keycode and a device code that is attached to said keycode and a device code that is attached to said keycode and that is specific to said keyboard, and wherien said controller is further provided with means which identifies the device code.

3. A cordless keyboard according to claim 1, wherien said sending means of said controller, sends back said keycode by attaching thereto a device code that is different from said device code that was received attached to said keycode.

4. A data processing apparatus having cordless communication between a keyboard and a controller, comprising:

a controller module having a display, a controller, and transmission means interconnecting said display and controller for transmitting data;

a keyboard module including a keyboard, and generator means for generating first and next keycodes in response to keys being activated;

cordless communication means including transducer means in said controller module and transducer mean in said keyboard module for two-way sending and receiving of encoded radiation between said modules;

said keyboard module including means storing the first keycode;

said transducer means of said keyboard module transmitting fist radiation to said controller module that is encoded with said first keycode and with a keyboard device code that is unique to said keyboard module;

said transducer mean for said controller module including a decoder for obtaining the received keyboard device code and received first keycode from eh first radiation received, comparator means for comparing the received keyboard device code with a fixed code for producing a comparison signal, encoder means responsive to the comparison signal for encoding the received first keycode acknowledgement with a controller device code that is unique to said controller module only when the comparison signal shows a correspondence;

said transducer means of said controller module transmitting second radiation encoded with said first keycode acknowledgment and said controller device code;

said keyboard module transducer means receiving the second radiation from said controller module that is encoded with the fist keycode acknowledgment and the controller device code;

said keyboard module including decoder means for obtaining the first keycode acknowledgment and controller device code from the received second radiation;

said keyboard module having comparator means for comparing the fist keycode in said storage means and the first keycode acknowledgement separated by said keyboard module decoder means and producing a corresponding correspondence or noncorrespondence signal; and

said storage means, said encoder means and said transmitting means of said keyboard module transmitting second radiation encoded with the fist keycode in said storage means and keyboard device code only in response to a noncomparison signal, and transmitting second radiation encoded with a next keycode and device code in response to a correspondence signal.

5. The apparatus according to claim 4, including said controller module having means for establishing a fixed time period;

and

said controller module transducer means, decoder means and comparator means being responsive to receiving second radiation within said fixed time period from said first reception for erasing the stored keycode and storing the first keycode of the retransmitting radiation, and being response to receiving second radiation encoded with the next keycode after the expiration of said fixed time period, for storing said next keycode in addition to said fist keycode.

6. The apparatus according to claim 5, including power means, exterior of said controller module, for providing power to said keyboard module.

7. The apparatus according to claim 6, wherein said power means includes means in said keyboard module for receiving power radiation and converting it into an electrical power supply for said keyboard module.

8. The apparatus according to claim 7, wherein said power means includes a receiving coil and a power supply circuit electrically connected to said receiving coil;

and said power means further including a power radiation supply module separate from said controller and keyboard modules, and including an electrical power supply and a high frequency transmitting coil electrically connected to said electrical power supply for providing electromagnetic radiation to said receiving coil.

9. The apparatus according to claim 4, wherien said transducer means transit light radiation.

10. The apparatus according to claim 4, wherein said first keycode acknowledgement is said first keycode.

11. The apparatus according to claim 10, including said controller module having means or establishing a fixed time period;

and

said controller module transducer means, decoder means and comparator means being responsive to receiving second radiation within said fixed time period from said fist reception for erasing the stored keycode and storing the first keycode of the retransmitting radiation, and being response to receiving second radiation encoded with the next keycode after the expiration of said fixed time period, for storing said next keycode in addition o said fist keycode.

12. The apparatus according to claim 4, including said keyboard module comparator means producing a correspondence signal only if the controller medevac code matches a fixed expected device code.

13. The apparatus according to claim 12, including said controller module having means for establishing a fixed time period;

and

said controller module transducer means, decoder means and comparator mean being responsive to receiving second radiation within said fixed time period from said first reception for erasing the stored keycode and storing the first keycode of the retransmitting radiation, and being response to receiving second radiation encoded with the next keycode after the expiration of said fixed time period, for storing said next keycode in addition to said first keycode.

14. The apparatus according to claim 13 wherien said first keycode acknowledgment is said first keycode.

15. The apparatus according to claim 12, wherein said first keycode acknowledgment is said first keycode.

16. A method of transmitting data between a keyboard module and a separate controller module, comprising the steps of:

p1 transmitting radiation from eh keyboard module to the controller module so that said radiation is encoded with a keycode specific to a key on the keyboard and with a device code uniquely specific to the keyboard module;

receiving said encoded radiation at the controller module and decoding it to obtain the keycode and device code;

sending radiation from h controller module to the keyboard module that is encoded with a keycode acknowledgement and a controller device code uniquely specific to the controller module only if the keyboard device code received matches a stored expected device code;

storing the received keycode as valid within said controller module only if the received keyboard device code matches the stored expected device code;

within said keyboard module decoding the radiation received from said controller module to obtain the controlled device code and keycode acknowledgement encoded herein; and

within the keyboard module, comparing the decoded controller device code with a stored expected device code and retransmitting the radiation encoded with the keyboard device code and keycode only of the decoded keycode is not equal to he keycode stored in the keyboard module; and

erasing the keycode stored in the controller module only if retransmitted radiation is received form the keyboard module within a fixed period of time after reception of the first radiation within said controller module.