The Emergency Medical Holographic Channel was a special communications channel used to communicate with the EMH on a starship. It could be accessed by activating monitor input 47. (VOY: "Parallax", "The Cloud", "Parturition", "Tattoo", "Dreadnought", "The Thaw", "Tuvix", "Basics, Part II", "The Swarm", "Fury")

In 2373, Tom Paris piggybacked an urgent message to The Doctor from a Class 2 shuttle on a fake Kazon signal being sent to USS Voyager's bridge. He reasoned that nobody would be monitoring the frequency. (VOY: "Basics, Part II")