This document explains the ZigBee Cluster Library (ZCL) and the ZigBee Device Profile (ZDP) in the CEL ZigBee Stack. The CEL ZigBee Stack supports the IEEE 802.15.4 and ZigBee2006 standards. The CEL ZigBee Stack includes Application Program Interface (API) functions to support the functionality defined in the ZigBee standard and the communication functions defined in the IEEE 802.15.4.