Abstract: A system and method for sending notifications of audio tone sequences to users in a push-to-talk over cellular communication system, including: decoding an audio transmission in a PTT (push to talk) server or in a PTT client, identifying audio tone sequences in the audio transmission, and sending from the PTT server or from the PTT client notifications of the identified specific audio tone sequences to users of cellular mobile devices, computers, and two-way radio communication devices. The notification may be a text message to a predefined PTT group, a delayed buffered replay of the audio transmission, the specific audio tone sequences with the audio transmission before and after the specific audio tone sequences; or an emergency alert sent to predefined members of a PTT group, or a combination thereof.

Abstract: Embodiments include a push-to-talk over cellular (PTToC) communication system and method having one or more push-to-talk (PTT) servers that control all PTT functionality for a set of users for receiving and transmitting audio communication over the Internet. A software defined radio (SDR) system is connected to the PTT server by means of a gateway and an internet gateway connection. The SDR system has software in a central processing unit which perform basic radio, audio frequency, and Internet networking functions, wide area connection, and routing functions that map radio channels to PTT talk groups by means of a radio channel routing table. The gateway adapts digitized audio between the SDR system and the PTT server and has a management application program interface client used by a central management entity to control the SDR system.