| 摘要 |
PROBLEM TO BE SOLVED: To provide a phone call system capable of simultaneously solving three inconveniences of reduction in voice due to a pressure-proof structure of a vessel with an apparatus necessary for phone call built therein and a diving depth, troubles of wearing a mouth mask or the like to be used for a diver to clearly speak, and carrying a speaker to emit voices of the diver. SOLUTION: Air in a space 10a inside a secondary pressure reducing valve at the same pressure as an ambient pressure is supplied to the vessel with the apparatus for phone call such as the speaker built therein by a vent pipe in the diving, so that a differential pressure between inside and outside the vessel is eliminated, a thin diaphragm easy for voice vibration can be used, and a pressure resistance limit according to the diving depth is eliminated. A diver can speak while holding a secondary pressure reducing valve 10 with an underwater speaker 13 integrated with a mouth mask 9 and opening and closing his/her mouth only by lightly biting a bite piece 35, and an operation is made to be simple and underwater communication is improved because the speaker always faces the speaking person. COPYRIGHT: (C)2007,JPO&INPIT
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