Signals and Receptions are used to model asynchronous communication between objects. Signal is a specification of a kind of communication between objects in which a reaction is asynchronously triggered in the receiver without a reply.

The data carried by the communication are represented as attributes of the Signal.

The sender of a Signal will not block waiting for a reply but continue execution immediately. By declaring a Reception associated to a given Signal, a Classifier specifies that its instances will be able to receive that Signal, or a subtype thereof, and will respond to it with the designated Behavior.

A Signal may be parameterized, bound, and used as TemplateParameters.