You may have certain communication needs that cannot be solved by just using hearing aids. These situations may involve telephone, radio, television, or the inability to hear the door chime, telephone bell, and alarm clock. Special devices have been developed to solve these problems. Like hearing aids, assistive listening devices and alerting devices make sounds louder. Typically, a hearing aid makes all sounds in the environment louder. Assistive listening devices and alerting devices can increase the loudness of a desired sound, like a radio or television, a public speaker, or an alarm system, or may make an auditory alarm (such as a smoke signal) into a visual alarm (such as a strobe light).