1、W 3400855 0133792 575 EUROPEAN w 1 ELECOMMUNICATION STANDARD ETS 300 679 September 1996 Source: ETSI TC-TE Reference: DETTE-04093 ICs: 33.020 Key words: Telephony, electrical coupling, hearing aids, PWSN Terminal Equipment (TE); Telephony for the hearing impaired; Electrical coupling of telephone se
2、ts to hearing aids ETSI European Telecommunications Standards institute ETSI Secretariat Postai address: F-O6921 Sophia Antipolis CEDEX - FRANCE Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE X.400: c=fr, a=atlas, p=etsi, s=secretariat - internet: secretariatetsi.fr Te
3、l.: +33 92 94 42 O0 - Fax: +33 93 65 47 16 Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. O European Telecommunications Standards Institute 1996. All rights reserved. ETSI
4、ETS*300*b79 9b I 3400855 0333793 401 9 Page 2 ETS 300 679: September 1996 Whilst every care has been taken in the preparation and publication of this document, errors in content, typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to “ETSI Editing and Co
5、mmittee Support Dept.“ at the address shown on the title page. ETSI ETS*300*679 96 3400855 0133774 348 Page 3 ETS 300 679: September 1996 Contents Foreword . 5 Introduction . 5 1 Scope 7 2 Normative references 7 3 Abbreviations . 7 4 Electrical characteristics 8 Point of connection in the telephone
6、set 8 4.2.1 4.2.3 Sensitivity 8 4.2.4 Frequency characteristic . 8 4.2.5 Maximum output 8 4.2.6 Noise . 9 4.2.7 Linearity check 9 4.3 Safety . 9 4.1 4.2 Electrical characteristics at interconnection point 8 Setting the acoustic receive and signal generator reference drive levels . 8 4.2.2 Impedance
7、. 8 5 Interconnection with the telephone set 9 6 Test procedures 9 Setting the reference drive level 9 Determining the electrical impedance at the interconnection point . 11 Measurement of the sensitivity 11 Determining the frequency characteristic 11 Determining the maximum output level . 11 Determ
8、ining the electrical noise level 11 Checking the input/output linearity . 11 6.1 6.2 6.3 6.4 6.5 6.6 6.7 Annex A (normative): Packaging. labelling and user instructions . 12 A.l Packaging and labelling 12 A.2 User instructions 12 A.3 Product Suppliers Information . 12 Annex B (informative): Rational
9、e for electrical output sensitivity chosen 13 Annex C (informative): Coupling to the hearing aid . 14 C.l Connector position 14 C.2 Interconnecting lead 14 Annex D (informative): Bibliography 15 History 16 ETSI ETS*300*679 96 I 3400855 0333795 284 I Page 4 ETS 300 679: September 1996 Blank page ETSI
10、 ETS*300*67q 96 3400855 0333796 310 Page 5 ETS 300 679: September 1996 Foreword This European Telecommunication Standard (ETS) has been produced by the Terminal Equipment (TE) Technical Committee of the European Telecommunications Standards Institute (ETSI). Transposition dates Date of adoption of t
11、his ETS: . 23 August 1996 Date of latest announcement of this ETS (doa): 31 December 1996 Date of latest publication of new National Standard or endorsement of this ETS (dop/e): 30 June 1997 Date of withdrawal of any conflicting National Standard (dow): 30 June 1997 Introduction This ETS is the thir
12、d in a series developed especially to meet the needs of people with hearing impairments who want to use the telephone. The first, ETS 300 381, covers inductive coupling and the second, ETS 300 488, covers additional amplification. This ETS covers the possibility of electrical coupling from a telepho
13、ne set to a hearing aid, and all three ETSs are in general accordance with ITU-T Recommendation P.37. This ETS is intended to be compatible with the IEC Publication 118, Part 6, which covers the characteristics of electrical input ports for hearing aids. It is anticipated that electrical coupling wo
14、uld benefit a limited number of users and should be regarded as an additional method and not a replacement for inductive coupling. It is envisaged that direct electrical connection between a hearing aid and a telephone set could be used in other applications that require electrical connection to the
15、 Public Switched Telephone Network (PSTN), for example to couple into other non-telephony amplification systems such as public address, or recording systems. Another alternative would be the direct electrical connection to a hearing aid transducer or headset, given that the device had sufficient sen
16、sitivity. Some of the applications envisaged would need to address safety and/or protection issues and, although these and the applications themselves do not come within the scope of ETSI standards, attention is drawn to them here for information. I-ETS 300 245-4 (covering the Additional Equipment I
17、nterface standard) could find application for coupling to the receive path of a telephone into a hearing aid. NOTE: It is possible that the system described could enable hearing aid users to use Iow- powered GSM (Group Special Mobile) telephones or DECT (Digital Enhanced Cordless Telephone). In this
18、 case some attention would need to be paid to ensure that disturbing signals are controlled sufficiently to prevent modulated carrier signals from interferencing with the hearing aid. It is not possible to be more specific at this stage. ETSI ETS*300*b79 96 I 3400855 0133797 057 Page 6 ETS 300 679:
19、September 1996 Blank page ETSI ETS*300*677 7b m 3400855 0333778 T93 = Page 7 ETS 300 679: September 1996 1 Scope This European Telecommunication Standard (ETS) specifies the electrical characteristics for the electrical coupling of the telephony function implemented in Terminal Equipment (TE) to hea
20、ring aids. It specifies the level and frequency response relative to the acoustic output at the earphone, and also the noise and maximum level. This ETS applies to all apparatus that is capable of supporting telephony and can be connected to the Public Switched Telephone Network (PSTN) or Integrated
21、 Services Digital Network (ISDN), which are intended for direct application to the ear, using for example traditional handsets or operators headsets, and which provide an electrical output port for the prime purpose of coupling electrically to a hearing aid. This ETS may also be invoked for mobile a
22、pparatus and apparatus having cordless handsets that provide the facility for electrical coupling to hearing aids. Although handsfree and loudspeaking devices are outside the scope of this ETS, if such apparatus also supports handset telephony as a separate function, this ETS may be invoked as part
23、of that function. 2 Normative references This ETS incorporates by dated and undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or r
24、evisions of any of these publications apply to this ETS only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. Pl ITU-T Recommendation P.57 (1 994): “Artificial ears“. IEC Publication 268-1 1 (1 987): “Sound System Equ
25、ipment Part 11 : Application of Connectors for the Interconnection of Sound System Components“. 31 CCIT Handbook on Telephonometry, ITU (1992). 41 151 ITU-T Recommendation P.64 (1994): “Determination of sensitivity/frequency characteristics of local telephone systems“. CCITT Recommendation P.53 (1 9
26、88): “Psophometers (apparatus for the objective measurement of circuit noise)“. 3 Abbreviations For the purposes of this ETS, the following abbreviations apply: dBVp ERP ISDN PSTN TE Decibels relative to 1 Volt, psophometrically weighted Ear Reference Point Integrated Services Digital Network Public
27、 Switched Telephone Network Terminal Equipment ETSI ETS*300*b? b 3q00855 0333799 2T Page 8 ETS 300 679: September 1996 4 Electrical Characteristics The bandwidth assumed for the requirements listed below is 315 Hz to 4 O00 Hz. If the bandwidth is different from this, e.g. as for wideband telephony,
28、then the extremes of the test frequencies shall be changed accordingly to accommodate the nominal bandwidth of such terminals. The following requirements and associated test methods assume the use of sine waves in one third octave sequences, or as appropriate for the equipment under test. For some a
29、pparatus it may be more appropriate to use other types of signal if it can be shown that such signals yield equivalent results. Unless otherwise stated all the requirements given below are for the volume control (if present) set to give maximum output. 4.1 Point of connection in the telephone set Th
30、e interconnection to the hearing aid shall be taken from the electrical path to the handset earphone so that the sidetone path is coupled into the hearing aid. Also, it shall not be possible to inject a signal into the telecommunication network from this point. Compliance shall be tested by inspecti
31、on. 4.2 Electrical characteristics at interconnection point This ETC assumes that the load normally applied by a hearing aid input circuit will be 2 O00 ohms resistive, as specified in IEC 118, Part 6 (see annex D). 4.2.1 Setting the acoustic receive and signal generator reference drive levels The s
32、ignal generator reference drive level that produces a sound pressure level of - 14 dBPa at 1 O00 Hz at the ERP (Ear Reference Point) shall be determined in accordance with subclause 6.1. This reference drive level shall be used for measuring the impedance, sensitivity and frequency characteristics s
33、pecified in subclauses 4.2.2, 4.2.3 and 4.2.4. 4.2.2 Impedance The modulus of the electrical source impedance between the frequencies of 31 5 Hz and 4 O00 Hz, or over the nominal bandwidth of the telephone set if greater than this, shall be less than 1 O00 ohms for all settings of the volume control
34、 (if present). Conformance shall be checked using the test described in subclause 6.2. 4.2.3 Sensitivity With the reference drive level of the oscillator set to produce - 14 dBPa at the artificial ear, with the choice and use of the artificial ear in accordance with ITU-T Recommendation P.57 l (see
35、subclause 6.1), the electrical output at 1 O00 Hz shall be - 35 dBV .e. holding it, dialling, charging batteries, or any other function. C.2 Interconnecting lead Although outside the scope of this ETS the design of the interconnecting lead needs careful consideration as an integral part of the coupl
36、ing from the telephone set to the hearing aid. For example; - The flexible cord should be very lightweight but robust. - Consideration should be given to the provision of a purpose designed receptacle to enable the cord to be carried about and to reduce the risk of it becoming tangled so increasing
37、the fault liability. - Cords that might be used to couple GSM or DECT telephone handsets to a hearing aid may need to be screened to reduce interference from the radio frequency signals in the aid. - Attention needs to be paid to the connection at the hearing aid, bearing in mind that some hearing a
38、id users, particularly elderly users, may have lost some dexterity and find it difficult to make the connection into the aid itself. ETSI ETSx300xb79 96 ri 3400655 O133606 97T = Page 15 ETS 300 679: September 1996 Annex D (informative): Bibliography For the purposes of this ETS, the following refere
39、nces have been given for information: - ETS 300 381 (1994): “Telephony for hearing impaired people; Inductive coupling of telephone earphones to headng aids“. - ETS 300 488 (1996): “Terminal Equipment (TE); Telephony for hearing impaired people; Characteristics of telephone sets that provide additio
40、nal receiving amplification for the benefit of hearing impaired“. - LETS 300 245-4 (1 995): “Integrated Services Digital Network (ISDN); Technical characteristics of telephony terminals; Part 4: Additional Equipment Interface (AEI)“. - ITU-T Recommendation P.37 (1 994): “Coupling hearing aids to tel
41、ephone sets“. - - IEC Publication 118-6 (1 984): “Characteristics of electrical input circuits for hearing aids“. 73/23/EEC: “Council Directive of 19 February 1973 on the harmonization of the laws of Member States relating to electrical equipment designed for use within certain voltage limits“. NOTE
42、: Commonly referred to as the Low Voltage Directive. ETSI ETS*300*679 96 3400855 0333807 A2b Page 16 ETS 300 679: September 1996 September 1995 June 1996 September 1996 Public Enquiry PE 92: 1995-09-25 to 1996-01 -1 9 Vote V 105: 1996-06-1 O to 1996-08-1 6 First Edition ISBN 2-7437-0920-0 Dpt lgal : Septembre 1996
