ETSI EN 300 422-1 covers the minimum characteristics considered necessary in order to make the best use of the available frequency spectrum for audio PMSE and ALDs.

The present document specifies the minimum performance requirements and the methods of measurement of Assistive Listening Devices, radio microphones and in-ear monitoring systems. It does not necessarily include all the characteristics that may be required by a user, nor does it necessarily represent the optimum performance achievable.

The present document applies to equipment operating on radio frequencies up to 3 GHz (as shown in table 1) using analogue, digital and hybrid (using both analogue and digital) modulation.

The maximum power recommended for equipment covered by the present document is 250 mW for radio microphones and 10 mW for ALDs.

An exception to this are the Public Hearing Aids defined in the CEPT Report 004 [i.8] and subsequent ECC [i.10] and EC Decisions [i.9] on the ex ERMES band (169,4 MHz to 169,8125 MHz) where 500 mW is defined.

The present document also covers radio microphones used in the 863 MHz to 865 MHz band, with a maximum power of 10 mW.

Electromagnetic Compatibility (EMC) requirements are covered by ETSI EN 301 489-9 [i.4].