Provided is a human guard enhancing multiple site security system comprising one or more human guards, peripheral equipment positioned at one or more sites, said peripheral equipment comprising one or more of a plurality of sensors, video cameras, positioning systems, and mobile communication and data processing equipment, said peripheral equipment being further capable of collecting and transmitting event-related and environmental data, one or more checkpoint systems capable of receiving, processing into a standardized protocol, and further relaying the data received from said peripheral equipment, and of providing said one or more guards with information based on the data, and one or more stations capable of logging, processing, and reporting the data relayed from said one or more checkpoint systems to provide a security system status and to facilitate human supervision, situation analysis, decision making, and intervention. The system includes a computer implemented communications protocol, which is an XML based communications protocol for real time security alert monitoring purposes. The XML based communications protocol consists of numerous modules which receive and convert data messages from varying security devices and sensors, standardize, translate and send converted messages, and encrypt and decrypt said data messages.