Data input device and Keypad

Data input device noun - A device that can be used to insert data into a computer or other computational device.

Keypad and data input device are semantically related. In some cases you can replace term "Keypad" with "Data input device", this terms are similar.

Keypad noun - A keyboard that is a data input device for computers; arrangement of keys is modelled after the typewriter keyboard.

Data input device and keypad are semantically related. Sometimes you can use "Data input device" instead a noun "Keypad".