telephony vs transmission

telephony

noun
  • The act of sound transmission via the electromagnetic spectrum. 

  • The study and application of telephone technology. 

transmission

noun
  • The act of transmitting, e.g. data or electric power. 

  • The fact of being transmitted. 

  • An assembly of gears through which power is transmitted from the engine to the driveshaft in a motor car / automobile; a gearbox. 

  • Something that is transmitted, such as a message, picture, or a disease; the sending of such a thing. 

  • The passage of a nerve impulse across synapses. 

  • The passing of a communicable disease from an infected host individual or group to a conspecific individual or group. 

  • The right possessed by an heir or legatee of transmitting to his successor(s) any inheritance, legacy, right, or privilege, to which he is entitled, even if he should die without enjoying or exercising it. 

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