The Weather Channel uses special proprietary equipment that inserts information on current and future local weather conditions, and weather alerts issued by the National Weather Service and the Storm Prediction Center and National Hurricane Center, if it is viewed on a cable television provider. The original WeatherStar technology has been upgraded on larger cable systems to the IntelliStar, which incorporates "Vocal Local" to announce current conditions, weather bulletins and detailed local forecasts. Subscribers of satellite, IPTV and some smaller cable providers originally saw only a roundup of local TWC-sourced forecasts for major cities across the U. S. , as well as national and regional satellite and radar images, and severe weather watch and warning maps when active. However, satellite customers with newer systems or interactive TV receivers have the choice of "roundups" or localized forecasts. For both cable and satellite viewers, popular music (formerly smooth jazz) plays in the background during these segments. Some older WeatherStar units were still in use by small cable companies that couldn't afford to upgrade to the IntelliStar. The WeatherStar units are also able to overlay text-based local contact information over the national feed during certain business advertisements aired on the channel.