Office Light Communication Systems

I’ve observed several practices with light communication systems (a.k.a. doctor nurse call systems) to help the doctor know where to to go next, and it allows the staff to know where the doctors is currently. The first ones had to use wires built into the walls to function. Then they came out with wireless ones that anyone can install easily.
In this age of electonic medical records, many practices have a computer in each room and at workstations across the office. Why isn’t there a program out there to install on each machine in your office that does the same thing as the light systems? Build into it a secure instant messenger application while you’re at it. Why don’t the EMR vendors just package this into their software?
I’m always thinkin’, yessiree.