International Standards and Conformity Assessment for all electrical, electronic and related technologies



Reference HD 305 S1:1977
Title IEC reference coupler for the measurement of hearing aids using earphones coupled to the ear by means of ear inserts
Project Number 441
Abstract/Scope Describes a coupler for loading the earphone with a specified acoustic impedance when determining the physical performance characteristics, in the frequency range 200 Hz to 5 000 Hz, of air-conduction hearing aids using earphones coupled to the ear by means of ear inserts, e.g. ear moulds or similar devices. The use of this coupler does not allow the actual performance of a hearing aid on a person to be obtained. Its use is recommended as a simple and ready means for the exchange of specifications and of physical data on hearing aids.


Current Stage code 9599
Current Stage code date 2006-05-13
Current Stage code deadline  
Deadline date for vote  


Order Voucher  


IEC Technical Body IEC/TC 29
Reference Document IEC 60126:1973 (EQV)
Keywords Electroacoustics; Coupler
Note Supersedes HD 181 * D126/041: Withdrawn
Special National Condition(s)  


Categories - Aspects
Product Life Cycle


Deadline Date
9599 2006-05-13    
6060 1977-05-15 1977-01-01  

Implementation Dates

date of Ratification (DOR) (1) 1975-10-08
date of Availability (DAV) (2) 1977-05-15
date of Announcement (DOA) (3) dor + 6 months
date of Publication (DOP) (4) 1977-01-01
date of Withdrawal (DOW) (5) dor + 36 months


Supersedes HD_NO 181:200X
Superseded by  
Normative reference (6)  

(1) Date of ratification (dor) date when the Technical Board notes the approval of an EN (and HD for CENELEC), from which time the standard may be said to be approved

(2) Date of availability (dav) date when the definitive text in the official language versions of an approved CEN/CENELEC publication is distributed by the Central Secretariat

(3) Date of announcement (doa) latest date by which the existence of an EN (and HD for CENELEC), a TS or a CWA has to be announced at national level

(4) Date of publication (dop) latest date by which an EN has to be implemented at national level by publication of an identical national standard or by endorsement

(5) Date of withdrawal (dow) latest date by which national standards conflicting with an EN (and HD for CENELEC) have to be withdrawn

(6) This list of normative references is purely indicative. The only official list of normative reference is the list of the published standard.