| 摘要 |
PURPOSE:To facilitate the attachment of a wiretap detecting circuit and to ensure the interchangeability between a telephone containing a wiretap detector and another telephone containing no wiretap detector, by detecting a telephone wiretap through a wiretap detecting circuit and from the difference of voltage that is applied to a telephone line and then connecting the substrate of the wiretap detecting circuit to the handset connecting part of a telephone. CONSTITUTION:The change of voltage between X and Y of a telephone line is detected by a diode D, a transistors TRQ1-Q3, a light emitting diode LD, etc. This mechanism is formed on a printed circuit board 1 in the form of a wiretap detecting circuit. This board 1 is connected to a transmitter microphone M having transmitter connecting parts 3 and 4 and fixed with the microphone M by a cover screwed from above. The connecting part on the rear side of the microphone m is connected to the bottom surface of the board 1, and connecting surfaces 5 and 6 are formed to the parts 3 and 4 respectively. Thus the board 1 containing a wiretap detecting circuit can be simply attached to the microphone M of a telephone set, and the interchangeability is secured between a telephone containing a wiretap detector and another telephone containing no wiretap detector. |
