Mine Telephone

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Mine Telephone

 

a mine rescue wired-communications device that provides direct two-way communication with loudspeakers between an underground base and a mine rescue squad.

The Sh–1 mine telephone, which is used in the USSR, consists of a base set and two squad sets. The squad sets may be held in the hand or fastened to the work outfit with a spring hook. Semiconductor devices and printed wiring are used in the electrical components of the telephone sets, which are designed to operate with general-purpose cable drums.

The Sh–1 mine telephone is designed for continuous operation at temperatures of 0° to 50°C, at relative humidities of up to 90 percent, and under conditions of exposure to coal dust, foul air, and underground water. The telephone has a communications range of 5 km and operates continuously for 100 hr without replacement of the power source. It is sparkless and, together with its carrying case, weighs 4.8 kg.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.