Integrated Sevices Digital Network (ISDN); 3,1 kHz telephony teleservice; attachment requirements for handset terminals; english version ETS 300085:1990
Edition 1992-02

Terminal Equipment (TE) - Telephony for the hearing impaired - Electrical coupling of telephone sets to hearing aids; English version ETS 300679:1996
Edition 1997-11

Integrated Services Digital Network (ISDN); 3,1 kHz telephony teleservice; end-to-end compatibility requirements for telephony terminals; english version ETS 300082:1992
Edition 1992-06

Telephony for hearing impaired people - Inductive coupling of telephone earphones to hearing aids; English version ETS 300381:1994
Edition 1995-09

Integrated Services Digital Network (ISDN) - Audio characteristics of terminals designed to support conference services in the ISDN; English version ETS 300807:1997
Edition 1998-07