Mine pager to public telephone interconnect system

Author: Parkinson, Howard E.
Year: 1974
Document Type: BMRA
Issuing Agency: U.S. Bureau of Mines,
SUDOC: I 28.23:7976
Series: Report of investigations / United States. Bureau of Mines ;
Report Number: 7976
Subjects: Mine communication systems
Telephone in mining
Link: https://hdl.handle.net/2027/mdp.39015078484386

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