Abstract: The present invention provides a Cable Gateway for interfacing packet cable networks with Internet Protocol (IP) Multimedia Subsystems (IMS). The Cable Gateway includes an Embedded Multimedia Terminal Adaptor (E-MTA) Normalization function that includes translation software that normalizes E-MTA interfaces to appear to IMS as SIP user equipment and performs initialization, call signaling, registration, authentication and security. The Cable Gateway also includes a CMSS/Mw Normalization function that interworks calls going between the IMS and a Remote CMS and a Gate Controller function that implements signaling interfaces to a CMTS and allows the E-MTA Normalization function and the CMSS/Mw Normalization function to interact with the CMTS and normalizes call-flow protocols.