An alarm system controller is provided, having a packet data network interface; a security alarm system interface configured to communicate with security alarm sensors; and a controller configured to receive at least one input from the security alarm system interface, to process the at least one input to determine an alarm condition, and to communicate the alarm condition and a markup language interface through the packet data network interface. The packet data network interface may communicate with the Internet. An environmental control system interface may also be provided to communicate with an environmental control system and to communicate the markup language interface through the packet data network interface, wherein the packet data network interface is configured to control the environmental control system. The markup language interface may be, for example HTML or XML.