This standard specifies the Layered Implementation Guidelines (LIG) for the Control Network Protocol (CNP) Specification: ANSI/CEA-709.1-D. The CNP specification model is based on the ISO Open Systems Interconnection Reference Model. There are also important extensions to the 7-layer OSI Reference Model. Figure 1 shows the scope of this specification in reference to the CNP and companion specifications for handling various data-transport media at the lower ISO protocol layers. A dashed line is used to show that the scope of this standard is not as redundancy to the other specifications covering their respective layers but as a complement to those specifications in implementing them in an interoperable fashion.

In this standard, the guidelines for implementing a device based on CNP are specified to increase the ability for devices to interoperate?regardless of installer or manufacturer of the devices. Anything outside this boundary is covered in other parts of the standard. Similar specifications exist for CNP data-transport media.