Time code: Audio Applications   

Time code has many different applications although its most common application is to synchronize time-based media. 

In location recording a camera which generates time code linked with a location recorder which can record time code provides for fast and simple synchronization of image and sound in post production. The time code may also contain (in the user bits) information pertaining to the picture reel, date, etc. 

In MIDI studios time code may be used to synch a multitrack recorder to the sequencer application running on a computer. This allows the composer to use the same synthesizer or sampler to create many different layers of sound.  In post production audio studios SMPTE time code is used to synch audio recorders or Digital Audio Workstations to video playback. In recording studios, SMTPE is used to lock multitrack recorders together to increase the number of available tracks or to synch sequencers to recordings of live players. 
Of course most studios use a unique combination of some or all of the above situations.
Typical small studio application (scoring): 

Master is LTC (longitudinal time code) recorded on a HiFi VHS tape. Using a SMPTE to MIDI time code converter, a sequencer, running on a personal computer, slaves to the time code.

With this setup, while watching a video scene, the composer can play on a MIDI keyboard and have that music locked to the image. A time code DAT added to this system will allow the music to be mixed (while watching a synchronized video) and recorded to a stereo master DAT. 
See Also: 
Time Code    Time Code rates    drop frame
location applications    audio applications