A barker channel is a form of digital signage, operating in the form of a television channel that is entirely composed of sales promotion and advertising, usually marketing various features of the service carrying the channel. The name is derived from the circus barker, who stood outside a circus and shouted to passers-by to encourage them to enter to view the entertainment being provided by the attraction. The systems are similar to character generators (CG), incorporating features such as motion graphics and have the ability to play video clips controlled by broadcast automation systems.