Delivery of alarm system event data and audio over hybrid networks is described. In one embodiment, delivering alarm system event data includes detecting an alarm event and communicating alarm event data to a message processing gateway, evaluating service parameters of the alarm system and conditions of the alarm event data, forwarding the alarm event data and a voice channel code to a telecommunications switch, and opening a voice channel between the telecommunications switch and a central alarm monitoring station. In other aspects, delivering alarm system event data and connecting a voice channel further includes determining whether the voice channel remains open, forwarding a routing code to the alarm system, opening a voice channel between the alarm system and the telecommunications switch, and bridging the voice channel between the telecommunications switch and the central alarm monitoring station and the voice channel between the alarm system and the telecommunications switch.