Ethernet is a large and diverse family of frame-based computer networking technologies for local area networks (LANs). On top of the physical layer Ethernet stations communicate to each other by sending each other data packets, small blocks of data that are individually sent and delivered. As with other IEEE 802 LANs, each Ethernet station is given a single 48-bit MAC address, which is used both to specify the destination and the source of each data packet. Network interface cards (NICs) or chips normally do not accept packets addressed to other Ethernet stations. Adapters generally come programmed with a globally unique address but this can be overridden either to avoid an address change when an adapter is replaced or to use locally administered addresses.

Microchip's ENC28J60 is a 28-pin, 10BASE-T stand alone Ethernet Controller with on board MAC & PHY, 8 Kbytes of Buffer RAM and an SPI serial interface. With a small foot print package size the ENC28J60 minimizes complexity, board space and cost. Target applications include VoIP, Industrial Automation, Building Automation, Home Control, Security and Instrumentation.