What stations are you hearing this with? I've only ever hear it with Eaton. It wouldn't make sense to do that with volunteers, the doors would shut before anyone got to station. Are you hearing it with the Muncie city trucks? (ie. 1 rescue 2 pump ect)I was told this is a new system that Delaware County is using.The Touch tones I am hearing are control signals going out to the stations to open doors on the station for the emergency units can respond with a quicker responce time.