handset vs headphone

handset

noun
  • The part of a landline telephone containing both receiver and transmitter (and sometimes dial), held in the hand. 

  • A mobile phone. 

  • A hand-held device for remote control of a piece of equipment. 

verb
  • To typeset by hand. 

headphone

noun
  • A cushioned speaker placed on, over, or inside the ear, normally used in left/right pairs. 

How often have the words handset and headphone occurred in a corpus of books? (source: Google Ngram Viewer )