A communication 
system is provided that can be added to a legacy alarm 
system to provide a plurality of communication 
modes to a remote 
server system from the legacy alarm system and provide 
remote control and monitoring to a user of the system via two-way communication links. The communication system can be configured to communicate with an alarm processor of the legacy alarm system through use of a keypad 
bus typically used by the legacy alarm system for communication between the alarm processor and one or more keypads. Communication 
modes that can be provided by embodiments of the present invention can include, for example, communication over a public switched 
telephone network, cellular transmission, 
broadband transmission, and the like. The communication system can monitor all configured communication 
modes and determine which communication mode is the best for providing communication between the alarm system and the remote 
server. Through these communication modes and by virtue of being coupled to the alarm processor via the keypad 
bus, the communication system can provide both transmission to the remote 
server of the status and alarm condition of the legacy alarm system as well as provide control signals from the remote server to the legacy alarm system. The remote server provides pre-determined responses to information received from the alarm system, including providing alarm system condition information to a user or a monitoring 
station for response.