What is ZigBee and where is it used?

ZigBee is a low-power, low-data-rate wireless protocol based on IEEE 802.15.4, designed for IoT and smart home applications. Key features: Operates in 2.4 GHz (global), 915 MHz (Americas), and 868 MHz (Europe) bands. Data rate of 250 kbps (2.4 GHz). Supports mesh networking with up to 65,000 nodes. Low power consumption enabling years of battery life. Range of 10-100 meters. Uses DSSS and O-QPSK modulation. Network roles include Coordinator (one per network), Router (extends range), and End Device (low power). Applications include home automation, smart lighting, industrial sensors, and medical devices. Competes with Z-Wave, Thread, and BLE Mesh.