1. A method for establishing communication between an executing task on a packet-switched data network and a terminating apparatus on a circuit switched communication network, the packet switched data network being operatively coupled to the circuit switched communication network by one or more gateway apparatus, the gateway apparatus and executing task being addressable over the packet-switched data network through respective network protocol addresses, the terminating apparatus and gateway apparatus being accessible over the circuit switched communication network through respective telephone numbers, the method comprising the steps of: A. generating a telephone number domain name identifying a telephone number; B. supplying a telephone number domain name to a domain name server operatively coupled to the packet switched network; C. obtaining a network protocol address of a gateway operatively coupled to the packet switched network; D. establishing a communication connection with the terminating apparatus identified by the telephone number domain name: