The TD-2 microwave radio relay system is a recent addition to the telephone plant facilities for long distance communication. It is designed to supplement the coaxial system and to provide greatly expanded facilities for nationwide transmission of broad-band signals such as television pictures or large groups of message circuits. The system makes use of many microwave repeaters located 2S to 30 miles apart in line-of-sight steps. The great variety and number of components which make up such a system require the engineering of all components to close tolerances. This paper describes the system in some detail from the standpoints of overall objectives, component designs to meet such objectives and facilities for the maintenance of overall performance.