longitudinal time code (ltc)

a time signal placed in one of the tracks that run the length of a videotape; on some recorders, one of the audio tracks must be used for the LTC, while others provide a special time code track; the code is normally the SMPTE Time Code; LTC can only be read while the tape is moving

Time code which is recorded onto an audio or video cue track. LTC encodes the biphase time-code signal onto an analog audio or cue track as a modulated square-wave signal