An Interworking Gateway enabled to provide continuous conversion of Protocol Data Units (PDUs) of any one of a provisioned set of transport protocols to any other member of the set is disclosed. Each transport protocol is associated with at least one transport protocol unit comprising at least one signaling port, at least one receive path, and at least one transmit path. Receive paths are adapted to convert PDUs of respective transport protocols into a base format, and transmit paths are adapted to convert a stream of base format data into PDUs of respective transport protocols. Transport protocol units are autonomous modules. The Interworking Gateway permits telephone services to extend across different broadband telephony networks in today's telecommunications system of networks.