An apparatus for notifying of a circuit switched event over a packetized data network. The apparatus includes a packetized data modem and an interworking interface. The packetized data modem is configured to transmit and receive packetized data over a packetized data radio link. The packetized data modem has a tunneling link access control processor that is configured to encapsulate/decapsulate data for a subset of sub-layers corresponding to a link access control layer of a circuit switched network model. The interworking interface is operatively coupled to the packetized data modem via the packetized data network, and is configured to notify the packetized data modem of the circuit switched event. The interworking interface has a link access control/tunneling link access control processor that is configured to encapsulate/decapsulate the data when performing notification of the circuit switched event.