| 摘要 |
PURPOSE:To prevent acoustic coupling between a transmitter and a receiver at the inside of a handset, by directly coupling sound transmission holes at the back of the transmitter or the receiver with a hole or a plurality of small holes provided at the back side of the handset. CONSTITUTION:A handset 1 for telephone device contains a transmitter 3 and a receiver 2 of rear side open type. Further, a sound transmission through-hole 2-5 at the back side of the transmitter 3 or the receiver 2 is directly coupled with one or a plurality of holes provided at the back side of the handset 1. Then, a path of sound waves at the back side of the receiver 2 from the inside 1-1 of the handset 1 to the back side of the transmitter 3, can be eliminated, allowing to prevent the production of howling. |
