47 CFR 32.2231: Radio systems.

(a) This account shall include the original cost of ownership of radio transmitters and receivers. This account shall include the original cost of ownership interest in satellites (including land-side spares), other spare parts, material and supplies. It shall include launch insurance and other satellite launch costs. This account shall also include the original cost of earth stations and spare parts, material or supplies therefor.

(b) This account shall also include the original cost of radio equipment used to provide radio communication channels. Radio equipment is that equipment which is used for the generation, amplification, propagation, reception, modulation, and demodulation of radio waves in free space over which communication channels can be provided. This account shall also include the associated carrier and auxiliary equipment and patch bay equipment which is an integral part of the radio equipment. Such equipment may be located in central office building, terminal room, or repeater stations or may be mounted on towers, masts, or other supports.