I haven't seen a manufacturer definition of "communicating." My understanding is that it basically implies widely variable modes of heating/cooling/air delivery along with dedicated modes of data transfer and equipment operation controlled by smart thermostats and, optionally, zoning controls.
I do not know whether there are standards for communicating equipment which would imply capability of interoperation. A Carrier air conditioner, say, with a Lennox furnace.
I have the following Lennox equipment, installed in August 2012:
Harmony III, three dampers, three zones, one per floor (basement is conditioned space with its own thermostat)
3 Comfortsense 7000 thermostats, one per floor/zone
HCWP3-18 humidifier, controlled by a humidistat in the community return
Lennox Healthy Climate filter box with 5" MERV 16 filter
What I consider poor quality ductwork (leaky and restrictive in all the wrong places) with building cavities used as return ducts (panned joists).
The EL296 is a "communicating" furnace. But I believe that the XC16, the Comfortsense 7000s, and the Harmony III are not capable of communicating operation.
If this is the case I need to investigate purchasing different equipment. I would appreciate any comment or correction on what I wrote, then I do have a specific zoning/equipment question.