On March 1, 1994, Showtime and The Movie Channel in conjunction with rivals HBO and Cinemax implemented a cooperative content advisory system to provide to parents specific information about pay-cable programming content that may be unsuitable for their children; the development of the system—inspired by the advisory ratings featured in program guides distributed by the major premium cable services—was in response to concerns from parents and advocacy groups about violent content on television, allowing Showtime Networks and other premium services discretionary authority to assign individual ratings corresponding to the objectionable content depicted in specific programs (and categorized based on violence, profanity, sexuality or miscellaneous mature material). A revised system—centered around ten content codes of two to three letters in length—was implemented by Showtime and the other participating premium services on June 10, 1994.