# Stopping an ISDN protocol stack instance

Applications call isdnStopProtocol to stop an ISDN protocol stack instance. This function shuts down the ISDN protocol stack instance, and releases all on-board resources and buffers formerly used by the stack instance.

The ISDNEVN_STOP_PROTOCOL event returns the completion status of the stop request. If the stack instance stopped successfully, the value field in this event contains SUCCESS. Otherwise, the event returns another reason code.