CCTV, also known as video surveillance is the use of video cameras to transmit a signal to a specific place, on a limited set of monitors. It differs from broadcast television in that the signal is not openly transmitted. Though almost all video cameras fit this definition, the term is most often applied to those used for surveillance in areas that require additional security or ongoing monitoring. Though videotelephony is seldom called "CCTV" one exception is the use of video in distance education, where it is an important tool.[