Method and apparatus for character generation

• US 4,381,502 A
• Filed: 06/29/1981
• Issued: 04/26/1983
• Est. Priority Date: 11/21/1978
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Prame, Eric S.
• Primary Examiner(s): Caldwell, Sr., John W.
• Assistant Examiner(s): Crosland, Donnie L.
• Application Number:
  US06/278,778
• Time in Patent Office: 666 Days
• Field of Search: 340/365 S, 340/365 R, 340/365 G, 340/365 A, 178/17 R, 178/17 A, 178/17 C, 179/90 K, 179/90 R, 179/2 DP, 400/100, 400/472, 400/485, 400/486, 400/489
• US Class Current: 341/26
• CPC Class Codes: G06F 3/0235 using chord techniques G06F3/0234 takes precedence
• CPC Class Codes: H03M 11/08 by operating selected combinations of multifunction keys

Abstract

Generation of a character code for an alphabetic character is performed by depressing at least two keys in a sequence. The code is generated when the last key is depressed and the other keys in the sequence still are pressed, or when all keys in the sequence are released. Numerical character codes are generated by depressing only one key per character. A logic and storage means is provided having a number of registers, code converting tables and control circuits for storing the history of depressed keys and for generating character codes.

Claims

1. A method of generating character codes by means of a keyboard having a plurality of keys arranged spatially in rows and columns, an electronic scanning means for scanning said keys to detect actuations thereof, and to produce key identification codes for said actuated keys, each of said keys bearing a plurality of potential symbols to be generated by depression of that key, said symbols being arranged in a spatial array on the face of said key, said keyboard also having an encoding means for generating character codes in response to the detection of actuated key codes produced by said scanning means, said method comprising steps of:

selecting a first key for depression from among the spatial array of said keys on said keyboard, said selection being in accordance with the relative spatial position in said array that said first key bears to the other keys on said keyboard, which relative spatial position corresponds to the relative position of the desired character symbol in its said spatial array of possible character symbols on the face of a second said key in said array;

depressing said first key and generating a key code therefor as the result of said scanning;

depressing said second key and generating a key code therefor in response to said scanning, said second key being the one on which said desired character symbol appears in the relative spatial relationship to other possible character codes on the face of said key, said relative spatial position corresponding to the relative spatial position of said first depressed key in said array of keys on said keyboard, said first key being maintained in a depressed state contemporaneously with the depression of said second key;

depressing a third key in said array of keys on said keyboard while maintaining said first and second keys in a depressed state;

detecting the coincidence of contemporaneous depression of said first, second and third keys; and

encoding a character code corresponding to the desired character selected by said combined first, second and third key depression codes.

3. The method as described in claim 1 or claim 2, wherein:

there is further included a step of detecting the release of said keys by scanning thereof with said scanning means; and

said encoding step is performed upon detection of the release of the last said key to be depressed.

2. A method of generating a plurality of character codes by means of a keyboard having a plurality of keys arranged spatially in rows and columns, an electronic scanning means for scanning said keys to detect actuations thereof, and to produce key identification codes for said actuated keys, each of said keys bearing a plurality of potential symbols to be generated by depression of that key, said symbols being arranged in a spatial array on the face of said key, said keyboard also having an encoding means for generating character codes in response to the detection of actuated key codes produced by said scanning means, said method comprising steps of:

selecting a first key for depression from among the spatial array of said keys on said keyboard, said selection being in accordance with the relative spatial position in said array that said first key bears to the other keys on said keyboard, which relative spatial position corresponds to the relative position of the desired character symbol in its said spatial array of possible character symbols on the face of a second said key in said array;

depressing said first key and generating a key code therefor as the result of said scanning;

depressing said second key and generating a key code therefor in response to said scanning, said second key being the one on which said desired character symbol appears in the relative spatial relationship to other possible character codes on the face of said key, said relative spatial position corresponding to the relative spatial position of said first depressed key in said array of keys on said keyboard, said first key being maintained in a depressed state contemporaneously with the depression of said second key;

detecting the coincidence of contemporaneous depression of said first and second keys and storing said key scanned codes produced by said scanner therefor;

releasing said first key while maintaining said second key in a depressed condition and depressing a third key;

detecting the coincidence of contemporaneous depression of said second and third keys and storing the key codes generated by said scanning means therefor;

releasing said second key while maintaining said third key in a depressed condition;

depressing a fourth key contemporaneous with the depression of said third key;

detecting the coincidence of contemporaneous depression of said third and fourth keys and storing the key codes produced by said scanning means therefor;

releasing said third and fourth keys; and

encoding three character codes corresponding to the desired characters selected by said first and second, second and third, and third and fourth key code combinations from said pairs of depressed keys.