hi sir, nice explaination. What is difference between ascii anci and unicode UTF8 and UTF16? and what is font convert?
On 7/23/14, Him Prasad Gautam <[email protected]> wrote: > 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/[email protected]/ > > To unsubscribe send a message to > [email protected] > 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.. > 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/[email protected]/ To unsubscribe send a message to [email protected] 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..
