The SBS Interworking Node is the switch where either:
an incoming SBS trunk call is routed to a non-SBS trunk (Figure : 3),
or
an incoming non-SBS trunk call is routed to an SBS trunk (Figure : 4).
The SBS Interworking Node is either the SBS Originating Node or the SBS Terminating Node.
The SBS Interworking Node is the SBS Originating Node when a non-SBS trunk is interworked to an SBS trunk.
The SBS Interworking Node will be the SBS Terminating Node when an SBS trunk is interworked to a non-SBS trunk.
Feature interworking on SBS calls is supported only to the degree that Communication Manager currently interworks public/private protocols to/from QSIG signaling.