An environmental control system controls monitoring and operation of a multiplicity of disparate environmental control devices by determining an appropriate configuration for each control device and communicates corresponding monitoring and control commands to each device in accordance with its corresponding communication protocol over a selected I/O port. An operational instruction set includes a structural definition of an enterprise facility in which devices are defined by personality modules and communicate with a system host in accordance with a protocol defined in a protocol module. Facility implementation is defined by a node tree structure which collects suitable protocol nodes under a corresponding I/O interface port node. Device (personality) nodes are collected under corresponding protocol nodes, and data point nodes depend from their corresponding device nodes. Data points nodes are individually accessible by merely traversing the node tree using a URL-like notational structure, allowing off-site users to control and monitor environmental devices by issuing commands in the form of a URL.