Asynchronous Transfer Mode (ATM) is a connection-oriented packet switching technique that is universally accepted as the transfer mode of choice for Broadband Integrated Services Digital Network. Asynchronous transfer mode (ATM) is a cell-oriented switching and multiplexing technology that uses fixed-length (53 byte; 48 bytes of data, and 5 bytes of header information) packets - called cells - to carry various types of traffic, such as data, voice, video, multimedia, and so on, through multiple classes of services. ATM is a connection-oriented technology, in which a connection is established between the two endpoints before the actual data exchange begins. The problems related to the performance and quality such as delay replay and outside interferer specially when used the real time system the Objective To design a VoATM technology (Voice Over ATM) using OPnet simulation the methodology to achieve the objective of this research is by design a network using Opnet software to simulate a an VoATM network to make two voice devices contact to each other.