The CC163 POS-PHY Level 3 Slave Core implements the industry standard POS-PHY Level 3, 8/32-bit system interface between physical layer device and data link layer for Packet Over SONET (POS) applications. CC163 consists of two parts, Transmitter CC163T and Receiver CC163R. CC163 can be used in any physical layer device with single or multiple PHY (Physical Layer) ports in Packet Over SONET applications. It supports a packet-level interface that allows the transfer of data, through a rate-matching buffer, between a data link layer device and PHY device implementing POS. It can be used in applications like PPP, HDLC etc. The CC163 core can be used in conjunction with rate matching FIFOs like Conexant's CC371 Packet FIFO.