Glossary of Terms
 
  FSK  
  Frequency Shift Keying — A method of converting digital information into a signal which can be transmitted and recorded using a conventional audio system. FSK is used by MIDI sequencers to generate timing (clock) information so that it can be recorded on a conventional audio tape recorder.  
  Source: Yamaha  

Also refered as:
  Frequency Shift Keying
Related terms:
  MIDI   clock   sequencer