call back vs dial up

call back

verb
  • To telephone someone again at a more convenient time. 

  • To request someone's return. 

  • To return to a shop or residence one has previously visited. 

noun
  • Request for a second interview or audition, following a successful initial interview. 

dial up

verb
  • To telephone, to call on the telephone. 

  • To connect a computer to a modem. 

  • To increase the level (of something) by turning a dial, or (figuratively) as if by turning a dial. 

How often have the words call back and dial up occurred in a corpus of books? (source: Google Ngram Viewer )