SMPTE (see WFTD archive SMPTE) Time Code (see WFTD archive Time Code) was an adaptation of the time coding that was in use by NASA to track space flight. In its current form (as used by audio and video engineers) it is referenced to video frames and is based on a 24-hour cycle. Within the 24-hour period each frame is identified by the exact time with a unique SMPTE address number in hours, minutes, seconds, and frames (also sub frames can be addressed). The signal is comprised of 80-bit digital words that can be recorded on one track of a video or audio tape recorder using a modulated (see WFTD archive Modulation) audio carrier. SMPTE Time Code recorded on analog tape sounds about the same as the sound your fax or modem makes when transferring data. There are other types of time code, but SMPTE is now such a standard in the industry that the words “SMPTE” and “Time Code” are used almost interchangeably. There are many different variations of SMPTE in use today that we’ll eventually cover here.