a little more... yes there are 256-character in ASCII -- and the chances are, you have 100, 101, or 103 key keyboard.

so it seems you should be able to use the keys to type out almost the complete character set.. but lets look at your keyboard.

at the right, a number pad, with some keys commonly use to express algabraic functions.. (0-9, +, -,*,/, a dot.) 17 keys is all.. and all of them are duplicated on the typewriter type board.

Moving to the right, and bottom, 4 directional keys, (these too are ascii characters, used to position the cursor..)
above 6 other keys, which are also postitional keys, but some of these are Ascii! --home is an ascii code!

and above them 3 more, print screen, scroll lock, and pause..

On the main keyboard, some of the keys are ascii.. Enter for example (Hard Carriage return..boy that tells you something about ascii--its reference point is a manual typewriter!) and shift while not a ascii key, is used to get codes.. so while A= ascii 65, (there are 26 letters in the alphabet, lower case a is not 65 + 26, but rather 65 + 32..(97!) On most keyboards, you hav 2 alt keys, 2 del keys, 2 control keys, 2 shift keys, and finally 12 function keys. Most of the function keys do not have a standard ascii code designation..

They result is, you there are about 65 keys that print visible available for ascii text codes. (and about 15 keys with ascii code, (space!, home, enter (carriage return), the cursor movement keys.. etc.)

The first 32 ascii codes are really hard to reprogram, the remaining 224 are reasonable easy to program. (create your own font! add ligatures!)about half of the Ascii first 32 ascii codes have keys on the keyboard. many of the first 32 ascii characters are not "visible".

in Japanese, (i don't know about chinese) there is a roman character code that uses the western characterset to spell out Japanese words (ie, Tokyo) some words, like the name Michiko,(one word in "western" characters, can in kanji, have different meaning. (2 different sets of Japanese kanji)(homophones, as it were) soft ware is suppose to notice these, (and so are proofreaders!) and offer two sets of Kanji.

reality is, it's difficult and slow, which is why computers and even typewriters are not nearly as popular in Japan as Fax's and copiers are! many documents are still hand writen, and copied, not typed or word processors.

for more on ascii, just google..

here is a table showing ascii with decimal values
http://www.jimprice.com/ascii-0-127.gif