The SN75LBC088 attachment unit interface (AUI) concentrator chip (ACC) incorporates eight data terminal equipment (DTE) or station ports and one medium attachment unit (MAU) or global port on the same chip for connection to a local area network (LAN). Each station port emulates the driver/receiver functionality, timing, and signal response of a transceiver or MAU designed to meet the IEEE 802.3-1990 standard. The functional components of the ACC are a differential driver, collision detection driver, and a differential line receiver/squelch.