Terminal Equipment (TE); Telephony for the hearing impaired; Electrical coupling of telephone sets to hearing aids

To specify characteristics & related test methods for an electrical interface between telephone receivers & hearing aids. Applicable to both analogue telephony terminals & digital telephony terminals.

Terminalska oprema (TE) – Telefonija za slušno prizadete – Telefonski aparati, električno spojeni s slušnimi pripomočki

General Information

Status
Published
Publication Date
30-Nov-2003
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Dec-2003
Due Date
01-Dec-2003
Completion Date
01-Dec-2003

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Standard
SIST ETS 300 679 E1:2003
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Terminal Equipment (TE); Telephony for the hearing impaired; Electrical coupling of telephone sets to hearing aids33.050.10Telefonska opremaTelephone equipment11.180.15Aids for deaf and hearing impaired peopleICS:Ta slovenski standard je istoveten z:ETS 300 679 Edition 1SIST ETS 300 679 E1:2003en01-december-2003SIST ETS 300 679 E1:2003SLOVENSKI

STANDARD
SIST ETS 300 679 E1:2003

EUROPEANETS 300 679TELECOMMUNICATIONSeptember 1996STANDARDSource: ETSI TC-TEReference: DE/TE-04093ICS:33.020Key words:Telephony, electrical coupling, hearing aids, PWSNTerminal Equipment (TE);Telephony for the hearing impaired;Electrical coupling of telephone sets to hearing aidsETSIEuropean Telecommunications Standards InstituteETSI SecretariatPostal address: F-06921 Sophia Antipolis CEDEX - FRANCEOffice address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCEX.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariat@etsi.frTel.: +33 92 94 42 00 - Fax: +33 93 65 47 16Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and theforegoing restriction extend to reproduction in all media.© European Telecommunications Standards Institute 1996. All rights reserved.SIST ETS 300 679 E1:2003

Page 2ETS 300 679: September 1996Whilst 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 Committee Support Dept." at the address shown on the title page.SIST ETS 300 679 E1:2003

Page 3ETS 300 679: September 1996ContentsForeword.......................................................................................................................................................5Introduction....................................................................................................................................................51Scope..................................................................................................................................................72Normative references..........................................................................................................................73Abbreviations.......................................................................................................................................74Electrical characteristics......................................................................................................................84.1Point of connection in the telephone set..............................................................................84.2Electrical characteristics at interconnection point................................................................84.2.1Setting the acoustic receive and signal generator reference drive levels.......84.2.2Impedance.......................................................................................................84.2.3Sensitivity........................................................................................................84.2.4Frequency characteristic.................................................................................84.2.5Maximum output..............................................................................................84.2.6Noise...............................................................................................................94.2.7Linearity check................................................................................................94.3Safety...................................................................................................................................95Interconnection with the telephone set................................................................................................96Test procedures..................................................................................................................................96.1Setting the reference drive level..........................................................................................96.2Determining the electrical impedance at the interconnection point...................................116.3Measurement of the sensitivity..........................................................................................116.4Determining the frequency characteristic..........................................................................116.5Determining the maximum output level.............................................................................116.6Determining the electrical noise level................................................................................116.7Checking the input/output linearity.....................................................................................11Annex A (normative):Packaging, labelling and user instructions.........................................................12A.1Packaging and labelling....................................................................................................................12A.2User instructions................................................................................................................................12A.3Product Suppliers Information...........................................................................................................12Annex B (informative):Rationale for electrical output sensitivity chosen................................................13Annex C (informative):Coupling to the hearing aid.................................................................................14C.1Connector position............................................................................................................................14C.2Interconnecting lead..........................................................................................................................14Annex D (informative):Bibliography........................................................................................................15History..........................................................................................................................................................16SIST ETS 300 679 E1:2003

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Page 5ETS 300 679: September 1996ForewordThis European Telecommunication Standard (ETS) has been produced by the Terminal Equipment (TE)Technical Committee of the European Telecommunications Standards Institute (ETSI).Transposition datesDate of adoption of this ETS:23 August 1996Date of latest announcement of this ETS (doa):31 December 1996Date of latest publication of new National Standardor endorsement of this ETS (dop/e):30 June 1997Date of withdrawal of any conflicting National Standard (dow):30 June 1997IntroductionThis ETS is the third in a series developed especially to meet the needs of people with hearingimpairments who want to use the telephone. The first, ETS 300 381, covers inductive coupling and thesecond, ETS 300 488, covers additional amplification. This ETS covers the possibility of electrical couplingfrom a telephone set to a hearing aid, and all three ETSs are in general accordance withITU-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 electricalcoupling would benefit a limited number of users and should be regarded as an additional method and nota replacement for inductive coupling.It is envisaged that direct electrical connection between a hearing aid and a telephone set could be usedin other applications that require electrical connection to the Public Switched Telephone Network (PSTN),for example to couple into other non-telephony amplification systems such as public address, or recordingsystems. Another alternative would be the direct electrical connection to a hearing aid transducer orheadset, given that the device had sufficient sensitivity.Some of the applications envisaged would need to address safety and/or protection issues and, althoughthese and the applications themselves do not come within the scope of ETSI standards, attention is drawnto them here for information.I-ETS 300 245-4 (covering the Additional Equipment Interface standard) could find application for couplingto 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 low-powered GSM (Group Special Mobile) telephones or DECT (Digital EnhancedCordless Telephone). In this case some attention would need to be paid to ensure thatdisturbing signals are controlled sufficiently to prevent modulated carrier signals frominterferencing with the hearing aid. It is not possible to be more specific at this stage.SIST ETS 300 679 E1:2003

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Page 7ETS 300 679: September 19961ScopeThis European Telecommunication Standard (ETS) specifies the electrical characteristics for the electricalcoupling of the telephony function implemented in Terminal Equipment (TE) to hearing aids. It specifiesthe level and frequency response relative to the acoustic output at the earphone, and also the noise andmaximum level.This ETS applies to all apparatus that is capable of supporting telephony and can be connected to thePublic Switched Telephone Network (PSTN) or Integrated Services Digital Network (ISDN), which areintended for direct application to the ear, using for example traditional handsets or operator's 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 apparatus and apparatus having cordless handsets that providethe facility for electrical coupling to hearing aids.Although handsfree and loudspeaking devices are outside the scope of this ETS, if such apparatus alsosupports handset telephony as a separate function, this ETS may be invoked as part of that function.2Normative referencesThis ETS incorporates by dated and undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text and the publications are listedhereafter. For dated references, subsequent amendments to or revisions of any of these publicationsapply to this ETS only when incorporated in it by amendment or revision. For undated references the latestedition of the publication referred to applies.[1]ITU-T Recommendation P.57 (1994): "Artificial ears".[2]IEC Publication 268-11 (1987): "Sound System Equipment Part 11: Applicationof Connectors for the Interconnection of Sound System Components".[3]CCITT Handbook on Telephonometry, ITU (1992).[4]ITU-T Recommendation P.64 (1994): "Determination of sensitivity/frequencycharacteristics of local telephone systems".[5]CCITT Recommendation P.53 (1988): "Psophometers (apparatus for theobjective measurement of circuit noise)".3AbbreviationsFor the purposes of this ETS, the following abbreviations apply:dBVpDecibels relative to 1 Volt, psophometrically weightedERPEar Reference PointISDNIntegrated Services Digital NetworkPSTNPublic Switched Telephone NetworkTETerminal EquipmentSIST ETS 300 679 E1:2003

Page 8ETS 300 679: September 19964Electrical characteristicsThe bandwidth assumed for the requirements listed below is 315 Hz to 4 000 Hz. If the bandwidth isdifferent from this, e.g. as for wideband telephony, then the extremes of the test frequencies shall bechanged accordingly to accommodate the nominal bandwidth of such terminals.The following requirements and associated test methods assume the use of sine waves in one thirdoctave sequences, or as appropriate for the equipment under test. For some apparatus it may be moreappropriate 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 givemaximum output.4.1Point of connection in the telephone setThe interconnection to the hearing aid shall be taken from the electrical path to the handset earphone sothat the sidetone path is coupled into the hearing aid. Also, it shall not be possible to inject a signal into thetelecommunication network from this point. Compliance shall be tested by inspection.4.2Electrical characteristics at interconnection pointThis ETS assumes that the load normally applied by a hearing aid input circuit will be 2 000 ohmsresistive, as specified in IEC 118, Part 6 (see annex D).4.2.1Setting the acoustic receive and signal generator reference drive levelsThe signal generator reference drive level that produces a sound pressure level of - 14 dBPa at 1 000 Hzat the ERP (Ear Reference Point) shall be determined in accordance with subclause 6.1. This referencedrive level shall be used for measuring the impedance, sensitivity and frequency characteristics specifiedin subclauses 4.2.2, 4.2.3 and 4.2.4.4.2.2ImpedanceThe modulus of the electrical source impedance between the frequencies of 315 Hz and 4 000 Hz, or overthe nominal bandwidth of the telephone set if greater than thi

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