Enabling a display of closed captioning status upon detecting a code of a proper subset of closed-caption data codes

摘要

In a television system including closed caption circuitry for receiving and decoding closed caption data, a controller continually monitors the closed caption circuitry for an indication of the presence of any of a plurality of predetermined valid closed caption data codes. Every time any of the predetermined valid closed caption data codes is detected, a timer is reset to begin timing a predetermined time interval, and an on-screen display indicating that closed caption data are available is enabled. If a subsequent one of the predetermined valid closed caption data codes is not detected before the expiration of the time interval, then the on-screen display indicating that closed caption data are available is disabled. In another embodiment of the invention, a lamp is illuminated to indicate the availability of useful closed-caption data.