A radio/telephony interoperability architecture that facilitates intercommunications between a security services network, elected officials and/or emergency services network and a telephony management system for one-way and two-way security and/or emergency teleconferencing communications. The telephony system creates a session in which one or more session participants can communicate with front-line mobile radio operators (e.g., first responder personnel) and radio band components. Mobile radio systems can be accessed via circuit-switched and packet-switched networks with communications capable of existing between horizontal services entities (e.g., city fire and police) and vertical entities (e.g., city, state, and federal agencies and personnel). Furthermore, the presence of participants and potential participants is provided to authorized users to facilitate the establishment of such conferences. Notifications and alarms are used to alert participants and potential participants of important events.