A person uses the keypad on a telephone.
keypad definition by Webster's New World
keypad definition by American Heritage Dictionary
keypad - Computer Definition
A simple input device comprising a set of keys or buttons mounted on a keyboard or control panel associated with a computer, telephone, microwave oven, or other device or on a remote control device. See also keyboard.
A small keyboard or supplementary keyboard keys; for example, the keys on a calculator or the number/cursor cluster on a computer keyboard. See programmable keypad.