SCREEN DISPLAY DEVICE FOR MANUFACTURER'S SERIAL NUMBER

PURPOSE:To disable rewiring and erasure and to prevent alteration by providing a nonvolatile memory for storing the manufacture's serial number of equipment, a key means which indicates the screen display of the manufacture's serial number, and a means which reads the manufacture's serial number data out of the nonvolatile memory and displays the manufacture's serial number on the screen. CONSTITUTION:An EAROM 18 is an erasable and programmable read-only memory and stored with data on the manufacture's serial number of a television receiver. A microcomputer 16 when reading data to be displayed out of the EARM 18 sends character codes to a character generator 20 to generate display character data, which are projected on the television screen of a CRT 32. When a manufacturer's serial number setting mode is entered with a manufacturer's serial number setting mode key 70, a computer 16 displays a message of manufacturer's serial number writing OK on the television screen and writes the manufacturer's serial number on condition that the numbers of respective digits of an inputted password number coincide with those of a password number stored in an address of the EAROM 18 previously. Consequently, alteration is percluded.