| 摘要 |
PURPOSE:To share the electric power source part built in the housing by providing the interphone housing with highfrequency input and output terminals, by connecting a filter and permitting only a high-frequency wave to pass through said filter. CONSTITUTION:Right under receiving antenna 1, TV high-frequency amplifier 2 is provided and interphone master housing 10 is provided with high-frequency input terminal 4 and output terminal 5. Then, the low voltage of the commercial electric power source obtained from interphone electric power transformer 15 provided to housing 10 is applied to high-frequency transmission line 3 via high-frequency stopping filter 6 and terminal 4. A TV signal from amplifier 2 is applied to TV receiver 9 via transmission line 3, terminal 4, low-voltage stopping filter 7, terminal 5, and high-frequency branching line 8 to receive a TV broadcast. As a result, the interphone can be coupled with the TV device inexpensively without wide space by operating amplifier 2 by applying a low-voltage electric power, low in dangerousness, to transmission line 3. |
