This alarm system is designed to be a stand alone system or to connect to the RS-332 Extension unit. The single unit provides a great base, but the extension unit allows full control from either side of the bed. Together they produce great stereo sound and will allow you to set different alarm schedules and different alarm sounds and radio stations. It features the Humane Wake System in which the alarm starts at low, gentle volumes and progressively increases until shut off to ease the person out of sleep and into the live world.