Telemedicine encompasses medical practice, teaching,
and research with real-time interactions over distances
too great for unaided communication. It includes audio
and video transmissions, either separately or combined,
and can be done through mechanical (e.g., signal flags
or lights) or electronic means (e.g., telecommunications).
In many ways, telemedicine is a subset of medical informatics,
itself a rapidly developing field. Prior definitions have
been broader, including not only medical practice over
distance, but also simple information transfer.