Emergency medical holographic channel

From Memory Alpha, the free Star Trek reference.

The Emergency Medical Holographic Channel was used to communicate with the EMH in USS Voyager's sickbay, via ship's computers. It was necessary, at first, because The Doctor was not designed to have access to ship systems as readily as other crewmembers. As The Doctor's holomatrix was enhanced and upgraded, enabling him to communicate more easily, the EMH channel fell into disuse. (VOY: "Parallax", "The Cloud", "The Thaw"}