This specification provides Ethernet physical parameters and data link layer specifications for use in a commercial aircraft environment. This specification provides general and specific guidelines for the use of IEEE 802.3 compliant Ethernet, 2000 edition. Physical layer and Medium Access Control (MAC) sub-layers are expected to comply with the Open System Interconnection (OSI) Reference Model to enable maximal utilization of off-the-shelf components, both hardware and software, for aviation use. The Ethernet Physical layer specification defines the electrical and optical parameters for the 10BASE-T, 100BASE-TX, and 100BASE-FX Ethernet implementations. This specification references ARINC Specification 600: Air Transport Avionics Equipment Interfaces for definition of copper-based implementations of the Ethernet Physical layer.