The IEEE 802.3cg 10BASE-T1L specification has simultaneously solved many problems of industrial communication by allowing 10-Mbps full-duplex communications up to a distance of 1,000 meters through a single pair of twisted wires, which can already be taken advantage of with the DP83TD510E single-pair Ethernet PHY. Furthermore, the standard also includes Power over Data Lines (PoDL) as the single-pair alternative to Power over Ethernet (PoE). This allows designers in the factory and building automation markets to use familiar Ethernet based protocols for long-distance communication between industrial controllers and sensors, with TCP/IP protocols from the Ethernet protocol suite being the basis for OPC UA, MQTT and HTTP. PoDL allows for this while also reducing wiring, as well as converging and simplifying their existing 4 mA to 20 mA or field-bus communication networks. A 10BASE-T1L PoDL system is composed of a Power Sourcing Equipment (PSE), a link segment and a Powered Device (PD). This document provides an overview of such a system and describes in detail how to design a 10BASE-T1L class-12 compliant PoDL PD.