Technical Notes

The Thumbscript Standard: Revised 11/2/2001.

Thumbscript is built on a 3x3 grid with 9 positions numbered as on the telephone keypad.

All letters are based on a pictograph using two strokes. The first stroke starts at one of the outer 8 buttons or positions and ends at the center (#5) button or position. The second stroke originates at the #5 position and stops on another of the outer 8 positions.

To enter alphanumeric data into a keypad, the user first presses the (Start) key corresponding to the start of the first stroke, then presses the (Stop) key corresponding to the end of the second stroke. In this way each character or command is represented by a sequenced pair of keystrokes.

To enter alphanumeric data into a pen or touch based device, the input area is divided into a grid of 3x3 cells. At the center of each of the outer cells, a dot is placed as a target to guide the user. The user places the pen down in the position of the beginning of the first stroke and lifts the pen in the region of the end of the second stroke. While the user may draw the pictograph as described above, it is also permissible to make a straight line from the beginning position to the ending one.

When both beginning and end of the pictograph are on the same key, the keypad implementation requires a double press of the key. The pen-based implementation requires only a tap with pen-down and pen-up in the same position.

Order of Keystrokes: All letters are fromed from top to bottom. Where Start and Stop are on the same row, the order is from left to right. In all cases the Start key is a smaller number than the Stop key. There are 28 possible combinations following this rule. 26 of them are used for the letters A-Z. The remaining two are used for the Enter function and the wild card character. (See undocumented characters below) The opposite order is used for punctuation and math symbols.

Straight Strokes: There are 4 possible letter pictographs in which the first stroke and the second stroke form a straight line through the grid. These are reserved for the vowels E(3-7), I(2-8), O(4-6), U(1-9).

Letters are formed as much as possible with a resemblance to the letters of the Roman Alphabet.

Math symbols are formed to the extent possible with a pictograph resembling the symbol.

Numbers are fromed starting with a keypress of the key corresponding to the number. as printed on the telephone keypad. A second keypress of the center (5) key completes the number. In the case of the number five, the center key is double pressed or in pen-based systems, tapped once. The 0 is formed like the letter "o" but with the order of key presses reversed (right to left).

Punctuation follows the pairings on the standard QUERTY keyboard in which punctuation marks are shifted versions of the number keys. Exception is made for the 5 key, since the double press used to form the number 5 cannot be reversed. Therefore the % sign is assigned to the reverse of the number 9, and the left parenthesis normally associated with the 9 key is treated as a math symbol (9-1).

Double press (or single tap for pen-based implementations) of the 8 outer keys are reserved for major functions plus space, period and comma.
"Undocumented" characters and functions:
In order to simplify the learning process, the standard printed Thumbscript key may omit some key combinations. The following are reserved to complete the functions of the standard computer keyboard:

6-7 emulates the Enter key for Macintosh and other keyboards that distinguish between Enter and Return keys. (Note this is one of the two top-bottom combinations that is not a letter.)

3-4 provides a wild card letter. This is the other top to bottom combination that is not a letter. This combination may be used in Thumbscript devices as a wildcard in any search.

4-3 is "Mod" a modifier key used for the extended character set.

6-1, (reverse "q") is the escape sequence.

9-2, (reverse "b") is equivalent to PC "Alt" key. (as opposed to the double-one used for functions in Thumbscript)

7-6 is reserved. In the Palm OS, it is used to initiate menu equivalents.

9-4, (reverse "h") is reserved. In the PC environment, it is used to emulate the function keys 1-12.

Extended Character Set:
These combinations are not intended to be memorized, but to be easy to remember for those who use them frequently.

Mod T Trademark
® Mod R Registered Trademark
© Mod C Copyright
Mod ` Left single quote
Mod ' Right single quote
Mod \ Left double quote
Mod / Right double quote
§ Mod S
° Mod o (Degree- Type the letter o)
± Mod +Plus/Minus
£ Mod L Pound
¥Mod YYen
¢Mod $Cent
Mod E Euro (not implemented in Palm OS 3.1)
¿Mod ? Inverted question mark
¡Mod ! Inverted exclamation point
ßMod B
µMod UMicron
ƒMod F
ØMod 0 (Type the Number 0)
Accents: First type desired letter, then Shift + accent
ÈShift + 1 Grave accent
ÊShift + 2 Circumflex accent
ÉShift + 3 Accute accent
ÃShift + 4 Tilde over letter
ÄShift + 5 Umlaut accent over letter.
ÂShift + 6 Ring: small circle accent over letter
ÆShift + 7 Ligature
ÇShift + 8 Cedilla accent
Shift + 9 Reserved.

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