An optical-fiber cable has been developed which has a superior performance; which has high reliability; which can be installed in lengths of 1 km or more by direct burial or in ducts without additional protection; which can be handled with the equipment and personnel regularly employed for conventional wire cables; which will withstand the rough treatment normally encountered in a field environment. The paper describes cable construction; measured results; methods of installation, splicing, testing and pressurization; specialized hardware; instruments and tools developed for field use. Several systems employing this type of cable have been installed and have been placed under observation with automatic monitoring equipment.