 These systems commonly have their front end units referred to as Turrets and are notable for their presentation of hoot-n-holler circuits.Multiple Hoots are presented to multiple users over multiplexed speakers to multiple locations.A PBX is a telephone exchange or switching system that serves a private organization and permits sharing of central office trunks between internally installed telephones, and provides intercommunication between those internal telephones within the organization without the use of external lines.