The APS layer implements application profiles, clusters, and endpoints. You can think of these as describing the general kind of thing you’re doing (profile), the more specific action you’re taking (cluster), and the location within a device where that action will be carried out (endpoint). On the XBee, these APS messages are all sent and received by special API frames (see Next steps). We’ll go through the concepts one by one to make it easier to understand them.
ZigBee application profiles are collections of common definitions and protocols that allow various devices to work together in a particular domain, such as home automation. Each profile defines device types and required functionality. The most interesting profiles are the public ones that are developed and maintained by the ZigBee Alliance—the official standards organization for the ZigBee protocol—so that all ZigBee-certified devices from any manufacturer can interoperate in systems for:
...and new profiles that are added on a regular basis
For example, in the case of Smart Energy, the profile allows different brands of electric meters, thermostats, appliances, and in-home display units to share a common language. Any Smart Energy-certified brand of thermostat can request pricing data through any brand of certified electric meter to decide whether an extra three degrees ...