Central Station Receiving Equipment

  • Model #Type - H
  • ManufacturerE.T. Holmes
  • Product TypeReceiver
  • MaterialsBrass
  • MarketCommercial
  • PeriodN/A


The galvanometer would be connected to a direct phone line and was balanced by a variable resistor at the customer premise. If the current was too high (Alarm Circumvention Attempt) or telephone trouble, the galvanometer would latch the light on.