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Mining Publication: A Multiplexed Phone System for Small Mines
Keywords: Communications Mine phones
This page is archived for historical purposes and is no longer being maintained or updated. Contact NIOSH Mining if you need an accessible version.
Original creation date: July 1982
Authors: JR Means, G Bowser
Conference Paper - July 1982
Download PDF Document (0.60 MB)
NIOSHTIC2 Number: 20031849
The Sixth WVU Conference on Coal Mine Electrotechnology, Cooley-WL, ed., Morgantown West Virginia, Jul 28-30, 1982, 1982 Nov; :116-123
A new phone system was developed that provides eight full duplex communications channels over a single twisted shielded phone line, with no central switching station or line amplifiers. This system greatly simplifies installation and maintenance over that required with conventional switching systems. The system is based on microprocessor technology and digital frequency synthesis. Frequency division multiplexing is used over a bandwidth of approximately 300 kHz, and a baseband voice channel (compatible with conventional pager phones) is provided as a backup to assure communication if the multiplex features fail. Multiplex operations are controlled over a 30-kHz digital channel. The system is designed to operate with up to 16 km (10 miles) of cable plant and a maximum phone separation of 8 km (5 miles). The digital techniques permit a limited amount of monitoring and control capability to each phone. This consists of two pair of contact inputs or outputs, to be used as desired. These "flags" may be read or controlled by a dispatcher's phone.
Image of publication A Multiplexed Phone System for Small MinesConference Paper - July 1982
Download PDF Document (0.60 MB)
NIOSHTIC2 Number: 20031849
The Sixth WVU Conference on Coal Mine Electrotechnology, Cooley-WL, ed., Morgantown West Virginia, Jul 28-30, 1982, 1982 Nov; :116-123
See Also
Experience with an Integrated, Computer-Controlled Communications and Monitoring System at the Robena Mine
Medium-Frequency Propagation in Coal Mines
Mine Communications and Tracking Glossary
Research and Development Contract for Coal Mine Communication System: Volume 2 - Mine Visits
Theory on the Propagation of UHF Radio Waves in Coal Mine Tunnels
Through-The-Earth Wireless Real-Time Two-Way Voice Communications
U.S. Bureau of Mines New Developments in Mine Communications
Ultra-Low Frequency Through-the-Earth Communication Technology
Underground Mine Communications
Underground Mine Communications (in Four Parts): 2. Paging Systems
Page last reviewed: September 21, 2012
Page last updated: September 21, 2012
Content source: National Institute for Occupational Safety and Health, Mining Program
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