The system communication in is based on XBee wireless modules. Their wireless protocol uses a simple, cost-effective and battery-efficient approach to provide sensor and control applications with robust, reliable, self-configuring and self-healing networks.

XBee modules establish a mesh network, which has the following advantages:

• Network setup is simple;
• More flexibility to expand the network;
• All nodes can sleep. No single point of failure associated with relying on gateway or coordinator to maintain time synchronization. Allowing a node to sleep reduces power consumption, which is especially helpful for nodes that are battery powered;

Long Range Options: Available on XTend™, with range of up to 40 miles (64 km) for each hop;
Frame Payload: Up to 256 bytes. Improves throughput for applications that send larger blocks of data. Additionally, the wireless protocol uses a simplified addressing method, which improves network setup and troubleshooting;
Interoperability: Proprietary;
Interference Tolerance: 900 MHz: Frequency-Hopping Spread Spectrum (FHSS);
Addressing: MAC address (64 bit);
Protection against unauthorized access to the network: Once a network is established, access to the network is granted only if the MAC address of the device is among a list of trusted MAC addresses.