The idea of writing mechanically was patented on 7th July 1714 by Henry Mil; the first experimental gadget was made by a French man Xavier Progin in 1833. Random conversions in Devanagari came to market from time to time, but the most important models were the Nagari Lekhan Yantra by V. M. Atre and the Mistra - Hindi typewriter by Olympia.
The orthography of a script for typewriter is decided by the popular acceptance of common grapheme that fully represents the pronunciations of the language. There are a huge numbers of joint letters and it is not possible to include them on keyboard of a conventional machine. So the literacy societies and the Government tried to simplify the Devanagari script, the simple form being named Bal-bodh.
This simplified Devanagari can be fully adapted on the conventional standard typewriter. The orthography of the letterforms in the simplified Devanagari script.
The typewriter’s roller moves over an equally towards left; the unit distance of such movement is termed as ‘spacing’. The size of the typeface is called ‘Pica’, when a roller moves by 10 spaces per linear inch and it is called ‘Elite’ when it moves by 12 spaces per linear inch and thus it varies with various sizes.
The distance by which the roller is lifted, when a shift key is pressed is termed as ‘motion’.
Dead Offset keys:
This mechanism influences the joining marks of Matras and the design of consonants.
The Rational solution (Phonetic Keyboard):
The committee report (1957) gave a very useful principal namely, ‘Put the most frequent letters on the most propitious positions.’ So the keyboard consist of ‘most propitious positions’, ‘most effort region’ and ‘most difficult region’, all within the ‘blind typing range’ and the rest in the ‘optical typing range’. And these letterforms are categorized in 3 graphic groups on the basis of Vertibar positions, as per Ganesh-vidhya analysis (Mid bar group, Top bar group, End bar group). So we can assign mathematical value to them and give differential value to places on the shift and un shift positions.
Grouping and Regional assignment:
High frequency (Home positions), Medium frequency (Middle region), Low frequency (Outer region), shift position.
Classification of characters:
The following classes are signs for the compositions of simplified (Bal-bodh) Devanagari grapheme which can print in all types of texts in Hindi, Marathi and Sanskrit.
Vertibar signs, End vertibar signs, Matras-cum-vertibar, Mid vertibar signs, Top vertibar signs-Unclassified signs, Numericals, Punctuation and others.
Institute of Typographic Research (ITR) Keyboard Layout:
ITR differentiates between Phonetics and Phonology. Phonetics is the term used by linguists in pronunciations as they exist in spoken languages. Phonology is a science of sounds which are classified according to organs of speech as per Vedas. ITR follows Phonological grouping of sounds together with positional value as well as the propitious use of frequency of occurrence of characters. Considering unshift and shift positions keyboard models can provide 106, 112,118, 120 and 126 characters or their double, about 106 characters are common in all and few additional characters are provided as per capacity.
Unshift positions of the Home row carries high frequent characters, their shift position carries phonetically nearer character; in addition, the central zone carries more frequent characters than those which are at extremes.
• Top Row - Signs, Numerical etc.
• Touch Zone - Blind Typing Region
• Upper Row - Labials, Semi vowels
• Home Row - Dentals, Gutturals, Sibilants
• Bottom Row - Vowels, Lingual’s, Matras
ITR provides maximum required about 400 characters and keyboard is designed with unshift, shift and control position with ligature routine. Scripts so far covered by ITR are Devanagari, Gujarati, Bengali, Oriya, Telugu, Kannada, Malayalam, Tamil, Simhala and Thai.