Will provide users of voice messaging systems with a consistent mode of interaction in a way that is independent of the underlying system implementations. The interface is based on a set of design guidelines defined in annex A. The interface supports the ability of all users described in the user-system model to access the features of voice messaging systems. In the call answering application, the interface allows callers to leave messages from all types of telephones. In the voice mail application, the interface allows subscribers to send and receive voice messages and to manage stored data.