in communication system , a packet data terminal , personal digital assistant , telephone , mobile radiotelephone , network access device , internet peripheral , and the like ) initiates , coordinates , and controls the provision of on - demand conference call and call waiting services as a function of user inputs without the need for coordination of network resources that dominate conference call service as currently known and practiced . the packet data terminal permits users to establish call conference services for originating and terminating calls , alike . in addition , multi - party call waiting services are established .