The combination of narrowband applications with broadband transport may be enabled with an intermediate signaling protocol that supports narrowband inter-domain bearer independent call control (BICC) signaling over a broadband network. For each setup request carried by the BICC signaling protocol, a seize device message is forwarded from a narrowband call control node to an intermediate entity responsible for converting the seize device message into a broadband endpoint request message. The interworking entity obtains broadband endpoint information from a selected broadband endpoint and creates a dynamic device representing the selected broadband endpoint. The dynamic device is used in the establishment of inter-domain switch connections.