Patent ID: 8634535

Claim:
A computer program product for operating a calling entity to transmit a communication event to a called entity located in a communication system comprising a first network and a second network, the program product comprising code embodied on at least one computer readable hardware storage device and configured so as when executed on a processing apparatus of the calling entity to: establish a connection to a network node in the second network; transmit data relating to the calling entity to said network node to establish a communication instance on the network node; receive a contact list from the communication instance comprising a second identity of the called entity; receive a first identity of the called entity from the communication instance, the first identity of the called entity allocated to the called entity by the communication instance by associating the first identity of the called entity with the second identity of the called entity, the first identity recognisable in the first network and the second identity recognisable in the second network; detect a user selection by a user of the calling entity to transmit the communication event to the called entity; and transmit the communication event using the first identity associated with the called entity to a gateway of the communication system operating on the first network.