Disclosed is a hub station of an alarm system, having: a hub station housing; a hub station controller disposed within the hub station housing, wherein the hub station is configured for: monitoring, over a short range telecommunications network, a plurality of client stations that are distributed in a plurality of architectural zones, the plurality of client stations each including a client station housing and located therein a client station power transformer, a client station speaker, a client station microphone, and one of a plurality of client station controllers; determining, from the monitoring, that an alert condition exists in the one of the architectural zones; and establishing a first bidirectional communication concurrently with two or more of the plurality of client stations distributed in the plurality of architectural zones.