Underground Mine Communications (In Four Parts). 1. Mine Telephone Systems (Including Articles on a Coaxial-cable Telephone System and Conventional Telephone Equipment).
NTIS: PB 270 187 :61 pages
This Bureau of Mines report is devoted to descriptions of systems that provide in-mine wired telephone service. Although they may incorporate other features, each system described functions to allow one telephone to selectively access another telephone. Except for the paper on conventional telephone equipment, the equipment described is newly developed and specifically designed to satisfy the requirements of underground mine communications.
IH; Information Circular;
NTIS Accession No.
NTIS: PB 270 187