1. An HVAC data processing and communication network, comprising: an active subnet controller configured to control networked devices via a data bus and configured to be addressed over said data bus; an environmental sensor configured to provide environmental data to said active subnet controller and configured to be addressable over said data bus independent of addressing said active subnet controller; and a user interface configured to provide access by an operator to said network and configured to be addressable over said data bus independently of addressing said active subnet controller and said environmental sensor; wherein said active subnet controller is located in an enclosure with at least one of said environmental sensor and said user interface, and said network further includes an inactive subnet controller, that is a different controller than said active subnet controller, configured to operate as said active subnet controller when said active subnet controller malfunctions.