terminal I/O

[lanmine]

When I read terminal I/O,I am confused somewhat.
1 "Suppose you type the letter x,the terminal send the ascii code..",what dose this sentence mean ,the terminal send ascii code?I can not understand ,I press the keyboard ,the keyborad send the ascii code to kernel,then what happened ?

2 "The letter x is placed in /input buffer/ and echo back to terminal ",which input buffer?
"echo back mean what"

3 Terminal I/O means serial ports I/O?


Thank you!

[Michael Tully]

I'm not exactly sure what you mean....

A terminal type is mapped to a file which contains escape characters, mapped to your keyboard. Now these mapping are determined by both the type of teminal mapping being used and the NLS (native language)
Echoing back to the screen is the actual map of the key.
Terminal I/O can be serial or via a psuedo terminal.

[lanmine]

Thank you for your reply,and forgive me not expressing myself clearly.

I mean I read some materials describing Terminal I/O's features.And I can not understand some of the words the book says.
My problem is:

when I press the one key of keyboard what happen next,how it can appear on screen? What are the steps to display the key I pressed ?

What is the terminal I/O input buffer ,output buffer?