SIST I-ETS 300 480 E1:2003

• Abstract:

  Specification of a harmonized set of test methods for testing the electro-acoustical characteristics for DE/TE-04004.1

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.040.35 - Telephone networks
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Dec-2003
• Due Date: 01-Dec-2003
• Completion Date: 01-Dec-2003
• Ref Project: ETSI I-ETS 300 480 ed.1 (1996-01) - Public Switched Telephone Network (PSTN); Testing specification for analogue handset telephony

SIST I-ETS 300 480 E1:2003 is the Slovenian adoption of European I-ETS 300 480, published by SIST and originally produced by ETSI. It specifies harmonized test methods for the electro-acoustical characteristics of analogue handset telephony terminals on the PSTN, so laboratories can compare terminals under the same test conditions.

The standard is aimed at conformance testing of analogue handset telephony equipment, with a focus on speech transmission performance and related effects such as noise, distortion, echo, instability and sidetone. It is a test-method document, not a product requirement document, so it tells users how to measure the terminal consistently.

What does SIST I-ETS 300 480 E1:2003 specify?

SIST I-ETS 300 480 E1:2003 specifies test methods for the conformance testing of electro-acoustic characteristics of analogue handset telephony terminals communicating across the European Public Switched Telephone Networks (PSTNs). Clause 1 also notes that access requirements are covered in another standard, ETS 300 001.

The document is organized into three main clauses and four annexes:

• Clause 1 covers the scope.
• Clause 2 lists normative references.
• Clause 3 lists abbreviations.
• Clause 4 contains the speech transmission compliance tests.
• Annex A is normative.
• Annexes B, C and D are informative.

Annex	What it covers
Annex A	Maximum signal sent to line
Annex B	Acoustic shock
Annex C	Immunity to out-of-band signalling
Annex D	Bibliography

In practice, this structure matters because the main body gives the core compliance methods, while the annexes add special tests for particular needs such as line drive, acoustic shock and signalling immunity.

What are the key requirements of SIST I-ETS 300 480 E1:2003?

Test conditions and setup

SIST I-ETS 300 480 E1:2003 requires tests to be carried out under laboratory conditions specified in ETS 300 001 and with defined measurement accuracy and test-equipment settings. Clause 4.1 also says tests may be run in any order unless stated otherwise, but when several feeding resistances are used they should be measured from the largest resistance downwards to reduce heating effects.

The document sets the handset mounting and acoustic setup so different labs can produce comparable results. The handset is normally mounted in the Loudness Rating Guard-ring Position (LRGP), or in the manufacturer’s normal-use setting if the microphone part is movable; where the mouthpiece and earpiece are separate, the geometry relative to the artificial mouth and artificial ear is defined. This matters because small position changes can alter measured loudness, sidetone and distortion.

Core speech transmission measurements

Clause 4.2 sets the main performance tests for sending, receiving and sidetone behavior. It includes sensitivity/frequency response measurements, loudness ratings, Sidetone Masking Rating (STMR), distortion, linearity, noise, Echo Return Loss (ERL) and instability checks.

These measurements are done with the terminal connected to the test arrangement in clause 4.1.10, using feeding resistance values selected from the standard’s prescribed range. In practice, this lets laboratories test the terminal across conditions that represent different line loads and then compare results against the relevant terminal standard.

Loudness, frequency response and sidetone

For sending and receiving sensitivity/frequency response, the document uses procedures from ITU-T Recommendation P.64 and measures across preferred frequencies from 100 Hz to 8 kHz at 1/12 octave intervals. Loudness ratings are calculated with ITU-T Recommendation P.79, and STMR is also derived from P.79 using the specified weighting method and terminating impedances.

This is important because loudness and frequency response are central to how natural a handset sounds in use. The same methods also support evaluation of sidetone, which is the portion of the user’s own voice heard back in the earpiece and which affects talker comfort.

Distortion, linearity and noise

Clause 4.2 includes harmonic distortion tests for sending, receiving and sidetone, plus power-handling checks and simple linearity tests at 1 000 Hz. Noise is measured separately for sending and receiving, with different weighting methods for the electrical and acoustic sides.

These methods matter for identifying terminals that add audible noise, compress levels, or distort speech when driven hard. The note in the clause also points out that the basic tests do not fully cover noise correlated with the signal or advanced non-linear processing, so users should be careful when comparing terminals that use such techniques.

Echo return loss and instability

SIST I-ETS 300 480 E1:2003 defines a procedure for measuring input impedance and calculating Return Loss and ERL over the voice band. It also includes an instability test that checks for sustained oscillation in a defined corner arrangement or, for separate mouthpiece/earpiece designs, in a free-air setup.

These tests matter because they help detect terminals that may echo, feed back or self-oscillate under realistic use conditions. For procurement or qualification work, they are useful indicators of how stable a handset will behave on the network.

Annex tests

Annex A gives the test used for maximum signal sent to line when the access requirement does not already include one. Annex B describes an acoustic-shock-related continuous-signal check, and Annex C describes how to evaluate the effect of out-of-band signalling such as meter pulses on speech performance.

Those annexes are useful when a project needs extra verification beyond the main speech tests. Annex C is especially relevant where signalling pulses can interfere with audio performance.

What terms does SIST I-ETS 300 480 E1:2003 define?

• Public Switched Telephone Network (PSTN) - The telephone network environment for which the terminal tests are intended.
• Terminal Equipment (TE) - The handset terminal being tested.
• Mouth Reference Point (MRP) - The reference point where the acoustic input to the sending side is applied.
• Loudness Rating Guard-ring Position (LRGP) - The defined handset placement used for most measurements.
• Sending Loudness Rating (SLR) - A calculated measure of how strongly the terminal sends speech.
• Receiving Loudness Rating (RLR) - A calculated measure of how loudly the terminal reproduces received speech.
• Sidetone Masking Rating (STMR) - A calculated measure of how much the user’s own voice masks sidetone.
• Echo Return Loss (ERL) - A measure used to characterize echo-related behavior from the terminal’s impedance response.

Who uses SIST I-ETS 300 480 E1:2003?

SIST I-ETS 300 480 E1:2003 is used by test laboratories, terminal manufacturers, conformance engineers, and quality managers who need a common method for checking analogue handset telephony performance. It is also relevant to buyers and procurement teams when they need to specify or verify electro-acoustic performance of PSTN handset equipment.

The standard is practical for organizations that must compare products, document test results, or support certification and acceptance testing. Because it defines the test arrangements and calculation methods, it helps different parties measure the same terminal in the same way.

Which standards are used with SIST I-ETS 300 480 E1:2003?

The document relies on several normative references and a related companion standard:

• ETS 300 001 (NET 4) - Provides general technical requirements for equipment connected to an analogue subscriber interface, plus the test environment and PSTN connection arrangement used here.
• ITU-T Recommendation P.64 - Provides the methods for sensitivity/frequency-characteristic measurements used for sending, receiving and sidetone.
• ITU-T Recommendation P.51 - Specifies the artificial mouth.
• ITU-T Recommendation P.57 - Specifies the artificial ear.
• IEC 651 - Specifies the sound level meter type used for acoustic measurements.
• CCITT Handbook on Telephonometry - Provides the basis for the d.c. feeding circuit.
• ISO 3 - Supplies the preferred-number series used for test frequencies.
• ITU-T Recommendation P.79 - Provides loudness-rating calculation methods and weighting factors.
• CCITT Recommendation O.41 - Provides psophometric weighting for noise measurements.
• ITU-T Recommendation G.122 - Provides the basis for ERL calculation.
• I-ETS 300 677 - Named in the foreword as the separate but complementary I-ETS for handset telephony requirements.

What does the SIST I-ETS 300 480 E1:2003 document contain?

SIST I-ETS 300 480 E1:2003 contains the full test structure for analogue handset telephony, including the standard test circuit, handset placement guidance, measurement conditions, and calculation methods. It uses figures for the transmission test arrangement, feeding-circuit tests, terminating impedances and instability placement, so the user can build the same setup in the lab.

It also contains a resistor-value table for selecting feeding conditions and several defined procedures for sending, receiving, sidetone, distortion, noise, echo and instability checks. The annexes add procedures for maximum signal to line, acoustic shock and out-of-band signalling immunity, which makes the document useful for design verification, compliance testing and technical audits.

SLOVENSKI STANDARD
01-december-2003
Javno komutirano telefonsko omrežje (PSTN) – Specifikacija preskušanja za
telefonijo z analognimi pogovorkami
Public Switched Telephone Network (PSTN); Testing specification for analogue handset
telephony
Ta slovenski standard je istoveten z: I-ETS 300 480 Edition 1
ICS:
33.040.35 Telefonska omrežja Telephone networks
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERIM
EUROPEAN I-ETS 300 480
TELECOMMUNICATION January 1996
STANDARD
Source: ETSI TC-TE Reference: DI/TE-04004.2
ICS: 33.020
Terminal equipment, PSTN, handset telephony
Key words:
Public Switched Telephone Network (PSTN);
Testing specification for analogue handset telephony
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - [e-mail]
X.400: Internet:
Tel.: [phone] - Fax: [phone]
*
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.
© European Telecommunications Standards Institute 1996. All rights reserved.

Page 2
I-ETS 300 480: January 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 Committee Support Dept." at the address shown on the title page.

Page 3
I-ETS 300 480: January 1996
Contents
Foreword .5
Introduction.5
1 Scope .7
2 Normative references.7
3 Abbreviations.7
4 Speech transmission compliance tests.8
4.1 General conditions for testing .8
4.1.1 Environment for tests .8
4.1.2 Accuracy of measurements and test equipment setting .8
4.1.3 Order of tests.8
4.1.4 Acoustic environment.8
4.1.5 Handset mounting .8
4.1.6 Test levels .9
4.1.6.1 Sending.9
4.1.6.2 Receiving.9
4.1.6.3 Sidetone.9
4.1.7 Volume control .9
4.1.8 Test equipment requirements .9
4.1.9 Alternative test methods.9
4.1.10 Testing arrangements .9
4.2 Speech transmission performance tests .12
4.2.1 Sensitivity/frequency response.12
4.2.1.1 Sending.12
4.2.1.2 Receiving.12
4.2.2 Loudness ratings.13
4.2.2.1 Sending.13
4.2.2.2 Receiving.13
4.2.3 Sidetone Masking Rating .13
4.2.4 Distortion .15
4.2.4.1 Sending.15
4.2.4.2 Receiving.15
4.2.4.3 Sidetone.15
4.2.4.4 Sending power handling capability .16
4.2.4.5 Receiving power handling capability.16
4.2.5 Linearity (variation of gain with input level).16
4.2.5.1 Sending.16
4.2.5.2 Receiving.16
4.2.6 Noise .17
4.2.6.1 Sending.17
4.2.6.2 Receiving.17
4.2.7 Echo Return Loss.17
4.2.8 Instability.18
Annex A (normative): Maximum signal sent to line .20
A.1 Maximum signal sent to line.20
Annex B (informative): Acoustic shock .21
B.1 Continuous signal.21

Page 4
I-ETS 300 480: January 1996
Annex C (informative): Immunity to out-of-band signalling. 22
C.1 Sending. 22
C.2 Receiving . 22
Annex D (informative): Bibliography . 24
History. 25

Page 5
I-ETS 300 480: January 1996
Foreword
This European Telecommunication Standard (ETS) was produced by the Terminal Equipment (TE)
Technical Committee (TE) of the European Telecommunications Standards Institute (ETSI).
An ETSI standard may be given I-ETS status either because it is regarded as a provisional solution ahead
of a more advanced standard, or because it is immature and requires a "trial period". The life of an I-ETS
is limited to three years after which it can be converted into an ETS, have it's life extended for a further
two years, be replaced by a new version, or be withdrawn.
This I-ETS is compiled as a separate, but complementary I-ETS to the requirements given in
I-ETS 300 677.
Proposed announcement date
Date of adoption of this I-ETS: 12 January 1996
Date of latest announcement of this I-ETS (doa): 30 April 1996
Introduction
This I-ETS provides a set of common test methods suitable for deriving the electro-acoustic requirements
of an analogue telephony terminal as described in clause 1 (Scope). These test methods do not exactly
simulate actual network components (e.g. local line sections, exchange feeding bridges) which are
different in each country, but provide a common basis for comparing the performance of different
telephony terminals.
Page 6
I-ETS 300 480: January 1996
Blank page
Page 7
I-ETS 300 480: January 1996
1 Scope
This I-ETS specifies test methods for the conformance testing of electro-acoustic characteristics of
analogue handset telephony terminals communicating across the European Public Switched Telephone
Networks (PSTNs).
NOTE: Tests for access requirements are contained in another standard e.g. ETS 300 001 [1].
2 Normative references
This I-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 revisions of any of these publications
apply to this I-ETS only when incorporated in it by amendment or revision. For undated references the
latest edition of the publication referred to applies.
[1] ETS 300 001 (NET 4): "Attachments to the Public Switched Telephone Network
(PSTN); General technical requirements for equipment connected to an
analogue subscriber interface in the PSTN".
[2] ITU-T Recommendation P.64 (1993): "Determination of sensitivity/frequency
characteristics of local telephone systems".
[3] ITU-T Recommendation P.51 (1993): "Artificial mouth".
[4] ITU-T Recommendation P.57 (1993): "Artificial ears".
[5] IEC 651: "Sound level meters".
[6] CCITT Handbook on Telephonometry, ITU, Geneva (1992).
[7] ISO 3 (1973): "Preferred numbers - Series of preferred numbers".
[8] ITU-T Recommendation P.79 (1993): "Calculation of loudness ratings for
telephone sets".
[9] CCITT Recommendation O.41 (1988): "Psophometer for use on telephone-type
circuits".
[10] ITU-T Recommendation G.122 (1993): "Influence of national systems on
stability talker echo in international connections".
3 Abbreviations
For the purposes of this I-ETS, the abbreviations in ITU-T Recommendation P.10 apply along with the
following:
ERL Echo Return Loss
LRGP Loudness Rating Guard-ring Position
MRP Mouth Reference Point
RL Return Loss
RLR Receiving Loudness Rating
SLR Sending Loudness Rating
STMR Sidetone Masking Rating
TE Terminal Equipment
Page 8
I-ETS 300 480: January 1996
4 Speech transmission compliance tests
4.1 General conditions for testing
4.1.1 Environment for tests
The environmental conditions which shall apply for the testing laboratory are specified in subclause 1.6 of
ETS 300 001 (NET 4) [1].
4.1.2 Accuracy of measurements and test equipment setting
Unless specified otherwise, the accuracy of measurements made by test equipment shall be equal to or
better than:
Item Accuracy
Electrical signal level
± 0,2 dB for levels ≥ - 50 dBm
± 0,4 dB for levels < - 50 dBm
Sound pressure ± 0,7 dB
Frequency ± 0,2 %
Unless specified otherwise, the accuracy of the signals generated by the test equipment shall be better
than:
Quantity Accuracy
Sound pressure level at ± 3 dB for frequencies from 100 Hz to 200 Hz
Mouth Reference Point (MRP) ± 1 dB for frequencies from 200 Hz to 4 000 Hz
± 3 dB for frequencies from 4 000 Hz to 8 000 Hz
Electrical excitation levels ± 0,4 dB across the whole frequency range.
Frequency generation ± 2 % (see note)
Specified component values ± 1 %
NOTE: This tolerance may be used to avoid measurements at critical frequencies,
e.g. those due to sampling operations within the terminal under test.
4.1.3 Order of tests
Tests are made in any order except where otherwise specified.
Where testing involves taking measurements using different feeding resistances, measurements shall be
made with the largest loop resistance, then at lesser values of resistance, decreasing sequentially to the
minimum, in order to avoid a heating effect in the test arrangement.
4.1.4 Acoustic environment
Acoustic tests shall be carried out in an environment where the ambient noise is insufficient to influence
the acoustic measurements being made.
Tests for noise and Echo Return Loss (ERL) shall be carried out in an environment where the ambient
noise is less than - 64 dBPa(A).
4.1.5 Handset mounting
Unless otherwise stated in a particular test, where the mouthpiece of the TE is fixed relative to the earcap,
the handset shall be placed in the Loudness Rating Guard-ring Position (LRGP) as described in annex C
of ITU-T Recommendation P.64 [2].
In the case of a moveable microphone part, measurements are to be carried at the setting for normal
usage as defined by the manufacturer.

Page 9
I-ETS 300 480: January 1996
Where the mouthpiece of the TE is separate from the earpiece, the front plane of the mouthpiece shall be
mounted 15 mm in front of the lip ring and coaxial with the artificial mouth.
The earcap shall be applied to the artificial ear.
4.1.6 Test levels
4.1.6.1 Sending
Unless otherwise stated in this I-ETS or in a relevant terminal standard, a pure tone signal with a sound
pressure level of - 4,7 dBPa shall be applied at the Mouth Reference Point (MRP) as described in ITU-T
Recommendation P.64 [2].
4.1.6.2 Receiving
Unless otherwise stated in this I-ETS or in a relevant terminal standard, a pure tone signal with an e.m.f of
- 12 dBV from a 600 Ω resistive source shall be connected between the terminals A and B shown in
figure 1.
4.1.6.3 Sidetone
Unless otherwise stated in this I-ETS or in a relevant terminal standard, a pure tone signal with a sound
pressure level of - 4,7 dBPa shall be applied at the MRP as described in ITU-T Recommendation P.64 [2].
4.1.7 Volume control
Where a user-controlled volume control is provided, compliance tests shall be carried out at a setting of
the volume control as specified in the appropriate requirement.
4.1.8 Test equipment requirements
Artificial mouth: the artificial mouth shall conform to ITU-T Recommendation P.51 [3].
Artificial ear: the ITU-T Recommendation P.57 [4] Type 1 shall be used unless another artificial ear
described in that Recommendation is requested by the terminal supplier.
Where a Type 1 ear is not used:
a) the sound pressure measurements shall be referred to the Ear Reference Point (ERP) by the
correction characteristics specified in ITU-T Recommendation P.57 [4];
b) no leakage correction shall be made in the calculations of Receiving Loudness Rating (RLR)
(i.e. L =0).
E
Sound level measuring equipment: the sound level measuring equipment shall conform to IEC publication
651 [5], type 1.
The d.c. feeding circuit shall be based upon subclause 1.2.3 of the Handbook on Telephonometry [6]. The
feed resistance values are specified in subclause 4.2 of this I-ETS.
4.1.9 Alternative test methods
The requirements of this test specification were written on the basis of the standard test methods
described in this I-ETS. For some parameters it is recognised that alternative test methods may exist. It is
the responsibility of the test house to ensure that any alternative method used is equivalent to that
described in this I-ETS.
4.1.10 Testing arrangements
All tests for transmission performance shall be carried out with the TE connected to the test arrangement
shown in figure 1.
Page 10
I-ETS 300 480: January 1996
A C
C
(See note 2) f
L
f TE
Artificial mouth
(see note 3)
B D
C
f
L
f Artificial ear
R
PSTN (see note 3)
f
connection
arrangement
(see note 4)
I
f
Feeding circuit
(See note1)
50V
NOTE 1: The d.c. feeding circuit shown is an idealised arrangement. Performance requirements
are given in figures 3 and 5.
NOTE 2 The equipment used for testing is connected between terminals A and B shown in and
consists of the following as appropriate: a signal generator, a measuring set, the
network either of figure 6, or figure 7, or figure 8 or a 600 Ω resistor.
NOTE 3: The artificial mouth and ear are described in ITU-T Recommendations P.51 [3] and
P.57 [4] respectively. The TE handset is mounted in the LRGP and the earcap is
applied to the artificial ear.
NOTE 4: The PSTN connection arrangement is described in ETS 300 001 (NET 4) [1].
Figure 1: Circuit for measurement of transmission characteristics
A C
C
f
L
ohms
f
ohms
B D
C
f
L
f
R
f
I
f
50V
Figure 2: Insertion loss test arrangement for the d.c. feeding circuit
When measured with the circuit shown in figure 2, the insertion loss of the d.c. feeding circuit shown in
figure 1 shall have a value less than that given in figure 3 (below) for all resistances and frequencies at
which it is used.
Page 11
I-ETS 300 480: January 1996
2 dB
1 dB
0,1 dB
10 20 50 100 200 500 1 000 2 000 5 000 10 000 Hz
Figure 3: Maximum limit for insertion loss
600 600
e=1V
ohms ohms
A C
C
f
L
ohms
f
U
ohms
B D
C
f L
f
R
f
I
f
50V
NOTE: In the absence of the d.c. feeding circuit, the return loss shall be greater than 40 dB.
Figure 4: Return loss test arrangement for the d.c. feeding circuit
When measured with the circuit shown in figure 4, the return loss of the d.c. feeding circuit shown in
figure 1 shall have a value greater than that given in figure 5 for all values of R and at all frequencies at
f
which it is used.
The return loss is calculated from the formula:
e
F I
RL = 20log dB
G J
H K
2U
where e is the generator voltage and U is the voltage measured by the measuring set.

Page 12
I-ETS 300 480: January 1996
dB
10 20 50 100 200 500 1 000 2 000 5 000 10 000 Hz
Figure 5: Minimum limit for return loss
4.2 Speech transmission performance tests
All tests for transmission performance shall be carried out with the TE connected to the test arrangements
specified in subclause 4.1.10.
Values of R are chosen from those given in table 1 to give the required range appropriate to the
f
requirement under test.
Table 1: Feed resistor R values
f
R 2 800 2 300 2 000 1 600 1 300 1 000 800 500
f (ohms)
NOTE: Assuming a voltage drop of about 7,5 V across the TE, the approximate currents given
above would flow. Actual currents will depend on the characteristics of the terminal.
Current (mA) 15 18 21 27 33 42 53 85
4.2.1 Sensitivity/frequency response
4.2.1.1 Sending
A measuring set calibrated in dBV, with an impedance of 600 Ω, shall be connected between terminals A
and B shown in figure 1.
The sending sensitivity/frequency response shall be determined by the procedure described in clauses 6
and 9 of ITU-T Recommendation P.64 [2]. The output voltage is measured at the fundamental frequency
of the stimulus. The results are expressed in dB V/Pa.
Measurements shall be made for R set to the appropriate value(s) given in the relevant terminal standard,
f
at 1/12 octave intervals at the preferred frequencies given by the R40 series of preferred numbers in
ISO 3 [7] for those frequencies from 100 Hz to 8 kHz that are specified in the relevant terminal standard.
4.2.1.2 Receiving
A signal generator shall be connected between terminals A and B shown in figure 1.
The receiving sensitivity/frequency response shall be determined by the procedure described in clauses 7
and 9 of ITU-T Recommendation P.64 [2]. The sound pressure is measured at the fundamental frequency
of the stimulus. The results are expressed in dB Pa/V.
Measurements shall be made for R set to the appropriate value(s) given in the relevant terminal standard,
f
at 1/12 octave intervals at the preferred frequencies given by the R40 series of preferred numbers in
ISO 3 [7
...