Cooling Requirements for Small Telephone Exchanges

This paper reviews the principal cooling requirements and techniques for small, and very small, local telephone exchanges (SLE and VSLE). The requirements described are the `whole-life' requirements. These requirements comprise the cooling methods; costs; equipment; manpower; materials; data and time factors associated with the cooling systems throughout their useful life. The environmental reliability requirements are described along with active and passive means of achieving thermally robust cooling systems. In this paper a small exchange is one of 2000 lines or less.