To provide a television monitor interphone system working such that, when a camera view field adjusting mechanism of a door phone slave unit with a camera is operated, the travel distance of the image of an object moving on a monitor screen is quantitatively visible to grasp an approximate amount of operation of the camera view field adjusting mechanism in displaying the object on a specified position on the monitor screen.

The television interphone system composed of a combination of a door phone slave unit 1 with a camera and a television interphone master unit 2 displays a grating pattern 3 on a monitor screen 21 of the master unit 2.