A dual token ring and Ethernet LAN interface chip

A CMOS LAN interface chip that combines the physical layer functions for both the token ring and Ethernet networks is described. The 4/16 mbps Token Ring interface exceeds the jitter tolerance (0.5 ns/UI) and accumulated phase slope (0.25 ns/UI) requirements at 16 Mbps of the IEEE 802.5 draft standard for STP/UTP transmission media. The 10 Mbps Ethernet interface supports both the AUI and 10BaseT functions of the IEEE 802.3 standard.