The DM9131 is a physical-layer, single-chip, lowpower transceiver for 100BASE-TX and 10BASE-T operations. On the media side, it provides a direct interface either to Unshielded Twisted Pair Cable 5 (UTP5) for 100BASE-TX Fast Ethernet, or UTP5/UTP3 Cable for 10BASE-T Ethernet, and it also provides PECL interface to connect the external fiber optical transceiver. Through the Media Independent Interface (MII), the DM9131 connects to the Medium Access Control (MAC) layer, ensuring a high interoperability among products from different vendors. The DM9131 uses a low-power and high-performance