It differs from broadcast television in that the signal is not openly transmitted, though it may employ point to point P2P, point to multipoint P2MP, or mesh wired or wireless links. Though almost all video cameras fit this definition, the term is most often applied to those used for surveillance in areas that may need monitoring such as banks, stores, and other areas where security is needed. Though Videotelephony is seldom called 'CCTV' one exception is the use of video in distance education, where it is an important tool. In industrial plants, CCTV equipment may be used to observe parts of a process from a central control room, for example when the environment is not suitable for humans. CCTV systems may operate continuously or only as required to monitor a particular event. A more advanced form of CCTV, utilizing digital video recorders DVRs, provides recording for possibly many years, with a variety of quality and performance options and extra features such as motion detection and email alerts.