Closed circuit simply means that the signal is not being broadcast any where, but rather is traveling by wire from the source to the recriver. Usually a closed-circuit television (CCTV) system uses a stand-mounted or hand-held video camera to project a magnified image onto a video monitor or a television (TV) screen. Traditionally video transmission in CCTV is done using 75 ohm coaxial cables. The video signal transmitted is generally normal composite video signal. although some systems use RF signals. CCTV video signal is comprised of both low frequency components (horizontal and vertical sync pulse information) and high frequency components (video information). In order to transmit this full spectrum of frequencies with little distortion or attenuation, it is important to select the correct coaxial cable that meets the specifications for CCTV transmission.