Abstract: A cooling system for communications equipment includes a closed container for housing the equipment and protecting the equipment against environmental influences. The container has an outer wall made of heat conductive material and is constructed for at least partial burial in the earth and for a heat transfer relationship therewith. A fluid filled conduit system includes conduits disposed outside the container and in heat transfer relationship with the outer wall thereof. The conduits outside the container are arranged to be buried in the earth for a heat transfer relationship with the earth. Heat conducting means are in thermal contact with the equipment and the container wall for transmitting heat generated by the equipment to the wall and to the conduit system. Thus, heat generated by the equipment is transferred to the fluid and heat in the fluid is transferred to the earth, and the fluid is circulated in the conduit system solely due to temperature and density variations of the fluid.

Abstract: A service integrated, time multiplex digital signal transmission system for transmitting narrowband and broadband signals between a central exchange terminal and a subscriber terminal, which system includes a optical fiber waveguide path connected between the terminals, a transmitter device at one terminal composed of sources of such narrowband and broadband signals and multiplexers connected for combining the signals provided by the sources into a multiplex signal and for supplying such multiplex signal to the optical fiber waveguide path, and a receiver device at the other terminal composed of demultiplexers connected to the optical fiber waveguide path for receiving multiplex signals from that path and separating the received multiplex signals into narrowband signals and broadband signals. The device at the subscriber terminal is normally supplied with operating power by local utility mains.

Abstract: A digital time multiplex communications system for transmission of a time multiplex signal containing the signal elements of a synchronization channel and of a plurality of communications channels. The receiver includes a member for separating the synchronization channel signal element from the communications channel signal elements of each frame. An externally triggerable sawtooth voltage generator connected to the separating member generates a sawtooth voltage sweep in response to the appearance of each synchronization channel signal element. A plurality of comparison stages each associated with a respective communications channel and connected to receive the sawtooth voltage and to produce an output signal when the sawtooth voltage reaches a respective value which differs by a fixed amount from one stage to the next such that the output signal from each stage occurs at a time corresponding to the appearance of a signal element of its associated communications channel.