| 摘要 |
PURPOSE:To facilitate a bidirectional private branch calling by utilizing a weak ratio wave and a faint radio wave effectively as a transmission medium in a limited range as a private branch. CONSTITUTION:When a call request of a terminal equipment 10 is inputted from a telephone set 3, it is informed to a call master equipment 8 via telephone circuit and loop antenna 7 and a private branch exchange 4. Then the equipment 8 sends a call signal in a weak radio wave 14 from a transmission antenna 9 to call the terminal equipment 10. On the other hand, the called terminal equipment 10 sends a reply signal in a weak radio wave 17, then the weak radio wave 17 is received by the caller main equipment 8 via a telephone circuit and loop antenna 7. The loop antenna is formed by utilizing the telephone circuit 7 of the telephone set 3, thereby utilizing a weak power in a limited range for the reply. |
