This Standard sets out requirements for the design, application and testing of assistive listening systems (ALSs). It also provides information to enable access to communication for people who have a hearing impairment or who are deaf.This Standard provides information in relation to varying degrees of hearing loss, and design solutions and equipment including - (a) assistive listening systems (ALSs), speech intelligibility and environmental interference; (b) assistive listening systems’ (ALSs) application in the built and transport environments, indoor and outdoor;(c) early warning systems - auditory, visual, and tactile requirements;(d) visual display systems for intercommunication, public announcements and the like; and(e) telephone services and telecommunications available to the public.