EXPLOSION-PROOF TELEPHONE SET

摘要

PURPOSE:To prevent explosion from being induced, by arranging an interface at a nonexplosion-proof area and a telephone set to an explosion-proof area, connecting the both with an optical fiber cable and detecting a call at the interface without the provision of a call bell for the telephone set. CONSTITUTION:An exchanger 10 is connected with an interface 40, to which a telephone set 20 is connected with an optical fiber cable 80. The telephone set 20 is installed at an explosion-proof area and the exchanger 10 and the interface 40 are arranged at the nonexplosion-proof area. The interface 40 is provided a detector for a callout signal and the detector is connected to an alarm device 101. In place of the device 101, a display device 102 can be provided at the explosion-proof area.