Electronic Voice Phenomena (EVP) is the term traditionally used to describe unexpected sounds or voices sometimes found on recording media. EVP initially involved audio tape recorders, but in later years, virtually any recording medium became a vehicle for phenomena. The term Instrumental TransCommunication (ITC) came into being to describe these expanded modes of audio- and video-format communication. Other acronyms used in the literature include Electronic Disturbance Phenomena (EDP) and Trans-Dimensional Communication (TDC).