Control track longitudinal timecode
Control track longitudinal timecode, or CTL timecode, developed by JVC in the early 1990s, is a unique technique for embedding, or striping, reference SMPTE timecode onto a videotape. Similar to the way VITC timecode is embedded in the vertical interval area of a video signal, CTL timecode embeds SMPTE timecode in the control track area of helical scan video recordings.
Source: Wikipedia — Control track longitudinal timecode (CC BY-SA 4.0)