An in-vehicle apparatus receives an image data representative of a screen image from a portable terminal with a touch panel. The apparatus extracts a text code data from the image data, and identifies a text-code display area in the screen image. The apparatus determines a command text based on a user-uttered voice command. The apparatus identifies a text-code display area as a subject operation area in the screen image of the portable terminal, based on the command text, the text code data extracted from image data, and information on the text-code display area corresponding to the text code data. An area of the screen image of the touch panel corresponding to the text-code display area is identified as the subject operation area, and a signal indicative of the subject operation area identified is transmitted to the portable terminal.