Patent ID: 7702079

Claim:
An adapter unit operatively connected to an Internet Protocol (IP) phone, comprising: a channel send-receive unit that sends signaling data to an exchange of a circuit-switched telecommunications network and receives signaling data from the exchange; a data packet send-receive unit that sends data packets via a data packet transfer network towards a first telecommunication system and receives data packets from the first telecommunication system via the data packet transfer network, the data packets sent and received during a normal operating mode; a data insertion-extraction unit that inserts the signaling data received by the channel send-receive unit into a data packet and forwards the packet to the data packet send unit and that extracts signaling data from a data packet received by the data packet receive unit and forwards the extracted signaling data to the channel send unit, the data inserted and extracted during the normal operating mode; and an operating mode switchover unit that switches over from the normal operating mode to an emergency operating mode if a fault occurs on the side of the data packet transfer network, wherein the emergency operating mode ensures telecommunication via the circuit-switched telecommunications network, and wherein the signaling data is not processed by the adapter during the normal operating mode.