Selective Paging and Intercommunication System

Details

• Personal Author:
  Schiffbauer, William H. ; Watson, Richard A.
• Description:
  A battery powered paging and intercommunication system for application in a mine or other environment where it is necessary to conserve battery power comprises a plurality of transceivers electrically coupled to a common pair of signal lines. Each of the transceivers includes a push-to-talk switch for applying voice signals onto the lines as well as a push-to-page switch that amplifies received voice signals for reproduction through a loudspeaker. Each transceiver also includes dual tone multifrequency (DTMF) encoder and decoder circuitry for addressing a preselected transceiver on the lines for paging. A timer circuit within the transceiver limits the period of time the transceiver limits the period of time the transceiver is in the paging mode to reduce battery consumption. As a system check during paging, the called transceiver generates "beep-back" signals on the lines indicating to the calling transceiver that it is receiving paging signals. A second timer circuit controls a light flasher at the called transceiver to serve as a call back signal. [Description provided by NIOSH]
• Subjects:
  Electrical Equipment And Supplies Mining Occupational Health Safety
• Keywords:
  Communications Equipment Electronic Equipment Mining Industry Radio Waves
• Series:
  Mining Publications
• Document Type:
  Text
• Genre:
  Other
• Place as Subject:
  OSHA Region 3 ; Pennsylvania
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PRC - Pittsburgh Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-9
• NIOSHTIC Number:
  nn:10002750
• Citation:
  US Pat 4,377,726 1983 Mar; :1-9
• Federal Fiscal Year:
  1983
• Peer Reviewed:
  False
• Source Full Name:
  United States Patent 4,377,726
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:044c5fc87a1685a5dc48e6eabbc1a4d39a25a98414e9ebbb36704b8df3cbc1a860dce6de913a2046d9fb9de20f937baca0f342921e1d3d0664383b8bc049061c
• Download URL:
  https://stacks.cdc.gov/view/cdc/219423/cdc_219423_DS1.pdf
• File Type:
  [PDF - 795.35 KB ]