This paper is an introduction to the ANSI/EIA/CEA-709.1 Control Networking Protocol, which is the most widely deployed control network protocol. This paper begins with an overview of networks and protocols, provides an overview of the ANSI/EIA/CEA-709.1 protocol, and describes a no-cost API that developers can use to develop devices based on the ANSI/EIA/CEA-709.1 protocol. Many of the technical details discussed in this paper are handled automatically by the protocol firmware, the network operating system, or network tools.