Digital communications satellite. Computer artwork of a communications satellite in space orbiting above the Earth, with a digital signal of zeroes and ones seen. Images, sound and computer data can all be reduced to zeroes and ones (binary digits) and transmitted at the speed of light around the globe. The satellite has solar cell arrays (blue) to produce power, and a rounded dish antenna to receive and transmit these digital signals. Communication satellites act to relay signals from ground stations or from other satellites. These satellites can carry telephone and fax messages, computer data, and can broadcast television signals.