A single-chip synchronous optical network (SONET) physical layer device includes first, second and third interface ports. An asynchronous transfer mode (ATM) interface circuit is coupled to the first interface port. A point-to-point protocol (PPP) processing circuit is coupled to the second interface...http://www.google.com.au/patents/US6075788?utm_source=gb-gplus-sharePatent US6075788 - Sonet physical layer device having ATM and PPP interfaces
