Mainly used on construction and temporary Hoists/Elevators, it is recommended by OSHA, and also considered the industry standard in the USA, Canada and Australia.
Communications is critical to provide workers a way to contact the elevator operator in case of an emergency. When a worker is hurt or suffers a heart attack, seconds count to get medical attention to that person.
Also as a general intercom system, allowing supervisors and workers to locate and communicate with each other. The down time that it takes to find personnel and to manage workers is reduced tremendously, thereby adding to the profit of the project