A system and method connects a call in a broadband system using the asynchronous transfer mode protocol for switching. Calls are connected over a SONET ring that has SONET multiplexers coupled by SONET paths. The SONET multiplexers are adapted to add calls to, and drop calls from, the SONET ring. An ATM cross connect system that has ATM cross connect devices is coupled to the SONET ring. The ATM cross connect devices provide provisioned ATM connections over the SONET ring. ATM interworking units are coupled to the ATM cross connect system. The ATM interworking units interwork calls with selected ATM connections in response to control messages. The selected ATM connections are provisioned between the ATM interworking units by the ATM cross connect system over the SONET ring. A signaling processor system receives call signaling for the calls, processes the call signaling to select the ATM connections for the calls, and sends the control messages to the selected ATM interworking units. The control messages designate the selected ATM connections.