Hi list, Many persons usually ask me what is unicode? Why screen reader work only in Unicode? Many VI fellows had requested me to make a system which may read non-uniCode letters which is not possible. They often complain that sited persons use non-uniCode system which they have to access. Here is a reply:
Let you be clear: 1. computer only knows every thing in number, no letter, word, or order. For example, if you press enter key, computer understand it as 13. number of key. like your roll number in school. 2. It does not recognize anything except numbers. 3. Though Computer knows only the numbers; the number must be either zero or one. two, three , four is not understood by it. 4. The two, three, four, ten, hundred or billion etc is converted into a different number that contain zero and one which called binary. 6. The binary number which contains only zero and one is taken as follows: zero means(switch off (no electric supply). 1 meansswitch on ( electric supply.). 7. That means computer does switch on and off only, it does not do any thing more. 8. The processor speed expressed in hertz means how many times can it do the switch on and off in one second. 9. A human being takes few second to on or off a switch, computer does the same work many billions times in one second. Now, perhaps you may have understood: 1. Computer does not recognize any letters. 2. Instead a letter name like a, b, c, a number of that letter must be given to it. Like you are called by your roll number by a teacher, or an immigrant officer called you by your passport number or some one refered you by your id number but not by your name. 3. Hope you conclude that in computer letters are dealt in numbers only but not by their name. Now the first question begins: How the letters are given numbers? What number is given for English alphabet a or for b or for c or for z or for ka/kha of Hindi, or for alif/bay of urdu? The numbering system of all letter of all languages of the world is called unicode. For example: Government decided to allocate a id number to all of Indian citizen. Now the id number can be given in either way: First method: Bengal: 1, 2, 3, 4, 5 .... Orissa: 1, 2, 3, 4, 5, .... Gujarat:1, 2, 3, 4,5, Kerala: 1, 2, 3, 4, 5.... In this method, the id number within a state is not repeated but the same id number holder is found in another state. Second method: Do not repeat the id number in each state. Allocate an unique number for an Indian citizen. Now come to the letter numbering system: This is an example: English letter: 1, 2, 3, 4, 5, Russian letter: 1, 2, 3, 4, 5 Hindi letter: 1, 2, 3, 4, 5, .... Punjabi letter: 1, 2, 3, 4, 5, ... Chinese letter: 1, 2, 3, 4, 5 This method of giving the number is called ASCII system. Where the letter number is repeated. Second way: English lettter: 1, 2, 3, 4, 5, ... upto 99 Russian letter: 100, 101, 102, 103, 104...upto 199 Hindi letter: 200, 201, 202, 203, 204... up to 299 Punjabi letter: 300, 301, 302, 303, ... up to 399. Chinese letter: 400, 401, 402, 403, 404 In this method, the letter numbers is not repeated! in different language. This is the Unicode system of coding. Now the final reply: It is already cleared that computer recognizes a letter by its code number; if the Unicode system is followed, it recognizes the exact letter because there is no repeating of the letter code number. If the letters coded in ASCII encoding, the repeat of number takes places and computer does not recognizes which language or letter it belongs. Take an example: if you went to a school and asked the headmaster about the performance of your kid having roll number ten; Can the headmaster exactly judge which is the student? Definitely not, because there are many students having roll number ten. If the school have a roll number system as in unicode; he can immediately know who is the kid because in Unicode there will be only one student having roll number ten in the school. Same case happens to screen reader to recognize the exact letter. That is why It recognizes if in Unicode but does not if in ASCII code. Him Prasad Gautam Kathmandu, Nepal Register at the dedicated AccessIndia list for discussing accessibility of mobile phones / Tabs on: http://mail.accessindia.org.in/mailman/listinfo/mobile.accessindia_accessindia.org.in Search for old postings at: http://www.mail-archive.com/accessindia@accessindia.org.in/ To unsubscribe send a message to accessindia-requ...@accessindia.org.in with the subject unsubscribe. To change your subscription to digest mode or make any other changes, please visit the list home page at http://accessindia.org.in/mailman/listinfo/accessindia_accessindia.org.in Disclaimer: 1. Contents of the mails, factual, or otherwise, reflect the thinking of the person sending the mail and AI in no way relates itself to its veracity; 2. AI cannot be held liable for any commission/omission based on the mails sent through this mailing list..
