A Power-over-Ethernet (PoE) communication system dynamically provides power and data communications over a communications link. In a computing environment made up of one or more personal computing devices (PCD) and/or one or more powered devices (PD), power source equipment (PSE) determines an allocated amount of power to be supplied to each device. The personal computing devices include a unified LAN-On-Motherboard (LOM) that combines the functionality of a powered device (PD) controller of a conventional PD and a LOM of a conventional personal computing device into a single unified subsystem. The unified LOM includes a standard or universal interface between the LOM and PD controller so that different types of PD devices with differing functionality can be easily married to the LOM, without requiring significant hardware or software redesign. The universal or standard interface includes a physical interface between the LOM and the PD controller and a compatible communication protocol to govern the communications between the LOM and the PD controller. This allows the LOM to be mixed and matched with any PD controller, enabling OEMs to economically provide multiple product models with varying degrees of PD and LOM functionality.