28. List the major components of the Keyboard Display interface. a. Keyboard section b. Scan section c. Display section d. CPU interface section 29. What is Key bouncing Mechanical switch are used as keys inmost of the keyboard. When a key is pressed the contact bounce back and forth and settle down only after a small time delay (about ms. Even though a key is actuated once, it will appear to have been actuated several times. This problem is called Key Bouncing.