The Ethernet interface processor (EIP) provides two, four, or six high-speed AUI (10 Mbps) ports. Each port supports both Ethernet Version 1 and IEEE 802.3/Ethernet Version 2 interfaces. A 16-million-instructions-per-second (mips) bit-slice processor provides a high-speed data path between the EIP and other interface processors. The EIP firmware (microcode), which contains card-specific software instructions, resides in a ROM in socket U101.