Explanation

Keyboard is an input device.

Keyboard is similar to electric typewriter.

Keyboard uses serial port to connect with computer.

Keys on keyboard are of mainly three types:

Alphanumeric keys: letters and numbers 

Punctuation keys: comma, period, semicolon, etc.

Special keys: function keys, arrow keys, caps lock key, etc. 
Keyboard inventor: Christopher Latham 

Smallest key on keyboard: Space key