ETSI EN 300 422-4 V2.1.1 (2017-05)
EN 300 422-4 specifies technical characteristics and methods of measurements for Assistive Listening Devices (ALDs) comprising personal hearing aid systems including inductive systems, personal sound amplifiers, and associated accessories for ALDs, e.g. remote controls and audio streaming devices.
It applies to equipment operating on radio frequencies up to 3 GHz using analogue, digital and hybrid (using both analogue and digital) modulation.