INTEGRATED USER NETWORK INTERFACE DEVICE

摘要

A user network interface device for interfacing between synchronous optical network (SONET)/synchronous digital hierarchy (SDH) which is , characterized by a continuous stream of frames of data and an asynchronous transfer mode (ATM) characterized by a non-continuous stream of cells of data. The user network interface device includes an integral phase lock loop circuit to recover clock and data from an encoded incoming stream of data. In another embodiment, the network interface device synthesizes a high speed transmit clock from a low frequency reference source.