The AOS provides a telco-grade platform for the continued support of legacy services such as 2/4 wire analogue leased line, ISDN, X.25 and Frame Relay over a fully supported NGN infrastructure without disruption to the end user, meaning that more customers and revenues are retained. The AOS is located in the central office, supporting a high number of legacy connections in a single device. It is built on state of the art server technology and provides a modern flexible architecture that enables legacy service delivery with minimal operational resources.