ETSI ETS 300 118 ed.2 (1996-05)

SLOVENSKI STANDARD
SIST ETS 300 118 E2:2003
01-december-2003
-DYQRNRPXWLUDQRWHOHIRQVNRRPUHåMH3671±6SHFLILNDFLMDNDWHJRULMH,,]D
SROGXSOHNVQHPRGHPH]DKLWURVWLEVLQDVLPHWULþQHGXSOHNVQHPRGHPH]D
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Public Switched Telephone Network (PSTN); Category II specification for 1 200 bits per
second half duplex and 1 200/75 bits per second asymmetrical duplex modems
standardized for use on the PSTN
Ta slovenski standard je istoveten z: ETS 300 118 Edition 2
ICS:
33.040.35 Telefonska omrežja Telephone networks
SIST ETS 300 118 E2:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 118 E2:2003

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SIST ETS 300 118 E2:2003
EUROPEAN ETS 300 118
TELECOMMUNICATION May 1996
STANDARD Second Edition
Source: ETSI TC-TE Reference: RE/TE-05049
ICS: 33.020
PSTN, modem, testing
Key words:
Public Switched Telephone Network (PSTN);
Category II specification for 1 200 bits per second
half duplex and 1 200/75 bits per second asymmetrical
duplex modems standardized for use on the PSTN
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 - secretariat@etsi.fr
X.400: Internet:
Tel.: +33 92 94 42 00 - 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.
© European Telecommunications Standards Institute 1996. All rights reserved.

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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.

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Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .7
3.1 Definitions .7
3.2 Abbreviations .8
4 General requirements .8
4.1 References to other ETSs .8
4.2 Information to be provided by the applicant.8
4.2.1 Information required for testing purposes .8
4.2.2 Instructions for use.8
5 Functional requirements specific to Category II modems .8
5.1 General requirements .8
5.2 Modes of operation/use .9
5.3 Line signals.9
5.3.1 Carrier frequencies.9
5.3.2 Spectral power .9
5.4 Line signalling rates .10
5.5 Channel allocation .10
5.6 Response times .10
5.6.1 Response times of the forward channel and backward channel received
line signal detectors.10
5.6.2 Response times of the forward channel ready for sending indicator .11
5.6.2.1 For modems with DTE control.11
5.6.2.2 For modems with control derived from the backward
channel .11
5.6.2.3 For modems which transmit carrier constantly when in the
on-line state .12
5.6.3 Response times of the backward channel ready for sending indicator.12
5.6.3.1 For modems with DTE control.12
5.6.3.2 For modems with control derived from the forward
channel .12
5.7 Synchronous mode of use .13
5.8 Thresholds of received line signal detectors.13
5.9 Auto-calling and auto-answering procedures.13
5.9.1 Auto-calling - calling tone .13
5.9.2 Auto-calling- recognition of answering tone .13
5.9.3 Auto-answering - answer tone.13
5.10 Provision of test looping facilities.13
5.11 Performance .14
5.11.1 Distortion .14
5.11.2 Receiver performance.14
Annex A (normative): Testing methods.15
A.1 General testing conditions.15
A.2 Test for subclause 5.3.1 (Carrier frequencies).15
A.3 Test for subclause 5.5 (Channel allocation).15

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A.4 Test for subclause 5.6 (Response times). 16
A.4.1 Test for subclause 5.6.1. 16
A.4.2 Test for subclause 5.6.2 (Data channel Ready For Sending (RFS) response times). 16
A.4.2.1 Test for subclause 5.6.2.1 . 16
A.4.2.2 Test for subclause 5.6.2.2 . 16
A.4.2.3 Test for subclause 5.6.2.3 . 17
A.4.3 Test for subclause 5.6.3 (Backward channel RFS response times) . 17
A.4.3.1 Test for subclause 5.6.3.1 . 17
A.4.3.2 Test for subclause 5.6.3.2 . 17
A.5 Test for subclause 5.7 (Synchronous mode of use). 18
A.6 Test for subclause 5.11.1 (Distortion). 18
A.6.1 Test for subclause 5.11.1 (a) . 18
A.6.2 Test for subclause 5.11.1 (b) . 18
A.6.3 Test for subclause 5.11.1 (c). 18
Annex B (informative): Proforma declaration of modes of operation/use. 19
Annex C (informative): Bibliography . 20
History. 21

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Foreword
This second edition European Telecommunication Standard (ETS) has been produced by the Terminal
Equipment (TE) Technical Committee of the European Telecommunications Standards Institute (ETSI).
This ETS contains the technical characteristics required for end-to-end interworking over the
Public Switched Telephone Network (PSTN) for 1 200 bit/s half duplex and 1 200/75 bit/s asymmetrical
duplex modems standardized for use over the PSTN.
These requirements are based upon, and do not conflict with, CCITT Recommendation V.23 [3] except in
the case of subclause 5.3.1 where the frequency tolerances specified are tighter than those given.
Additionally, requirements are included relating to end-to-end inter-operability over PSTN connections.
Such requirements are in excess of the CCITT/ITU-T Recommendations.
Except where otherwise stated, a modem which complies with CCITT Recommendation V.23 [3] should
always meet the requirements of this ETS which relate to parameters specified in that
CCITT Recommendation.
Clause 4 of this ETS references the requirements common to both Category I and II modems, which are
contained in final draft prETS 300 114 [1], clause 4. The definitions for Category I and Category II
modems can be found in the foreword of final draft prETS 300 114 [1].
Clause 5 of this ETS contains Category II requirements specific to 1 200 bits per second half duplex and
1 200/75 asymmetrical duplex modems. In the case of certain functions common to a number of different
types of modem (e.g. Auto-answering sequence) reference is made to clause 5 of final draft
prETS 300 114 [1] which contains the relevant requirements.
Transposition dates
Date of adoption of this ETS: 26 April 1996
Date of latest announcement of this ETS (doa): 31 August 1996
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 29 February 1997
Date of withdrawal of any conflicting National Standard (dow): 29 February 1997

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1 Scope
This ETS contains the technical characteristics required for end-to-end interworking over the
Public Switched Telephone Network (PSTN) of modems supporting:
- half duplex operation over the PSTN at 1 200 bit/s; and/or
- asymmetrical duplex operation over the PSTN at 1 200/75 bit/s
standardized for use over the PSTN, in accordance with CCITT Recommendation V.23 [3].
The objective of this specification, the application of which is entirely voluntary, is to provide the users with
an added degree of assurance that modems in compliance with this specification can interwork with each
other, under most network conditions.
The term "modem" in the context of this ETS includes all physical implementation practices for a voice
band modem, which is conductively connected to the PSTN.
This ETS specifies up to four modes of operation/use (see subclause 5.2).
This ETS also contains descriptions of the tests to be performed in order to confirm compliance with the
functional requirements contained herein. A general description of the test conditions and test
requirements is given in annex A (normative).
NOTE: To aid reading, the term "forward channel" is sometimes used to describe the channel
capable of transmitting up to 1 200 bit/s, and the term "backward channel" is similarly
used to describe the channel capable of transmitting up to 75 bit/s.
2 Normative references
This ETS incorporates, by dated or 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 ETS only when incorporated in it by amendment or revision. For undated references the latest
edition of the publication referred to applies.
[1] Final draft prETS 300 114 (1996): "Public Switched Telephone Network (PSTN);
Basic Category I and Category II specification for modems standardized for use
on the PSTN".
[2] ETS 300 001: "Attachments to Public Switched Telephone Network (PSTN);
General technical requirements for equipment connected to an analogue
subscriber interface in the PSTN".
[3] CCITT Recommendation V.23 (1984): "600/1200-baud modem standardized for
use in the general switched telephone network".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETS, the definitions contained in final draft prETS 300 114 [1] apply, together with
the following:
degree of start-stop distortion: In start-stop transmission the ratio of the maximum measured
difference, irrespective of sign, between the actual and theoretical intervals separating any significant
instant from the significant instant of the start element immediately preceding it, to the unit interval.
The highest absolute value of degrees of individual distortion of the significant instants of a start-stop
signal is reached within a specific time interval. The degree of distortion of start-stop modulation,
restitution or signal is expressed as a percentage. The result of measurement is completed by an
indication of the period of the observation. The start-stop distortion is positive when the significant instant
occurs after the ideal instant and conversely, negative when it occurs before.

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degree of synchronous start-stop distortion: Determined when the assumed unit interval is that
appropriate to the actual modulation rate. The degree of synchronous start-stop distortion is measured by
adjusting the scanning rate of the distortion measuring set. The start-stop distortion is positive when the
significant instant occurs after the ideal instant and conversely, negative when it occurs before. For the
determination of the actual mean modulation rate, account is only taken of those significant instants of
modulation (or restitution) that correspond to a change on the same sense as that occurring at the
beginning of the start element.
3.2 Abbreviations
For the purposes of this ETS, the abbreviations given in final draft prETS 300 114 [1] apply:
RFS Ready For Sending
TE Terminal Equipment
4 General requirements
4.1 References to other ETSs
The modem shall comply with final draft prETS 300 114 [1], clause 4.
NOTE: Final draft prETS 300 114 [1] in turn refers to ETS 300 001 [2] for the majority, if not
all, of its requirements.
4.2 Information to be provided by the applicant
4.2.1 Information required for testing purposes
The applicant shall declare for which of the modes of operation/use identified in this ETS, the modem is
supposed to undergo tests.
Compliance will be considered to have been accomplished by provision of the relevant information.
NOTE: This may be carried out by completion of forms such as those provided in annex B.
4.2.2 Instructions for use
Instructions for use shall be made available with the apparatus. The instructions for use shall include:
a) the apparatus or types of apparatus to which the instructions apply;
b) any information specifically indicated in this ETS for inclusion in the "Instructions for use"; and
c) any national restrictions on the use of the apparatus.
For the purpose of compliance with this ETS, any additional information shall be disregarded unless it is
subject of another ETS.
Compliance shall be checked by inspection.
5 Functional requirements specific to Category II modems
5.1 General requirements
To comply with the requirements of this ETS, it shall be necessary that the modem provide:
- half-duplex mode with switched carrier or asymmetrical duplex mode of operation/use with
continuous carriers, as specified in CCITT Recommendation V.23 [3];
- frequency shift binary modulation with synchronous or asynchronous mode of use;
- signalling rates of up to 1 200 bit/s in the forward channel and, optionally, of up to 75 bit/s in the
backward channel.

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NOTE 1: In the following, references are made to interchange circuits between the modem and
the DTE, as defined in CCITT Recommendation V.24. DTEs using certain customised
modems will generally not provide an interface with such interchange circuits.
For these cases the references to V.24 type interchange circuits indicate equivalent
functionality of a DTE and a modem.
NOTE 2: With asymmetrical duplex modems providing a CCITT Recommendation V.24
interface, it is common practice to provide the interchange circuit for the 75 bit/s
channel on the relevant pin for the 1 200 bit/s channel.
5.2 Modes of operation/use
It shall be possible to configure the modem to operate in at least one of the following modes of
operation/use:
a) 1 200/1 200 bit/s half duplex asynchronous;
b) 1 200/75 bit/s asymmetrical duplex asynchronous;
c) 75/1 200 bit/s asymmetrical duplex asynchronous;
d) 1 200/1 200 bit/s half duplex synchronous.
It is the applicant's responsibility to specify for which of these modes of operation/use the modem is
supposed to undergo tests.
NOTE 1: In the above representation, the first number indicates the rate at which data is
received, and the second number indicates the rate at which data is transmitted.
NOTE 2: In this ETS, a clear distinction cannot be made between mode of operation and mode
of use, and therefore no attempt has been made to separate the above list into these
categories.
5.3 Line signals
The channels defined are within the telephone bandwidth.
NOTE: The allocation of channels is described in subclause 5.5.
5.3.1 Carrier frequencies
The nominal characteristic frequencies are listed in table 1:
Table 1: Frequency allocation
Binary 0 (Fa) Binary 1 (Fz)
1 200 bit/s chl 2 100 Hz 1 300 Hz
75 bit/s chl 450 Hz 390 Hz
For modes a), c) and d), as defined in subclause 5.2, the characteristic frequencies Fa and Fz as
measured at the line terminals of the modem shall not deviate by more than ± 3 Hz for the 1 200 bit/s
channel; and for mode b) ± 2 Hz for the 75 bit/s channel (if provided in the modem) from those given in
table 1.
NOTE: These frequency tolerances are tighter than those specified by
CCITT Recommendation V.23 [3].
Compliance shall be checked by the method described in annex A, clause A.2.
5.3.2 Spectral power
The national network dependent spectral power limits are given in final draft prETS 300 114 [1], clause 4.
NOTE: This refers in turn to ETS 300 001 [2].

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5.4 Line signalling rates
Where the modem provides the relevant mode(s) of operation, it shall be capable of transmitting and/or
receiving data at line signalling rates of:
- up to 1 200 bit/s in modes a), b) and c);
- up to 75 bit/s in modes b) and c); and
- 1 200 bit/s in mode d).
Compliance shall be checked during the tests given in subclause 5.11.
5.5 Channel allocation
A modem operating in mode b) (1 200/75 bit/s - asymmetrical duplex modem), shall be capable of
responding to signals received in the 1 200 bit/s channel and transmitting signals in the 75 bit/s channel.
A modem operating in mode c) (75/1 200 bit/s - asymmetrical duplex modem), shall be capable of
responding to signals received in the 75 bit/s channel and transmitting signals in the 1 200 bit/s channel.
For modems capable of operating in both modes b) and c), at least one of following techniques of channel
selection shall be provided:
a) manual selection of the channel using facilities provided on the modem;
b) selection of the channel by the DTE, whilst in the on-line state. Two methods are recognised, either:
b.1) using a common control signal (equivalent: Using CcT 105):
when the DTE indicates that its wishes to transmit on the 1 200 bit/s channel, the modem
shall enable transmission on the 1 200 bit/s channel (equivalent: turning OFF CcT 105); and
when the DTE indicates that it no longer wishes to transmit on the 1 200 bit/s channel
(equivalent: turning OFF CcT 105), the modem shall enable transmission on the 75 bit/s
channel;
b.2) using separate control signals (CcT 105 and CcT 120):
when the DTE indicates that it wishes to transmit on the 1 200 bit/s channel (equivalent:
turning ON CcT 105), the modem shall enable transmission on the 1 200 bit/s channel; and
when the DTE indicates that it no longer wishes to transmit on the 1 200 bit/s channel
(equivalent: turning OFF CcT 105), the modem shall disable transmission on 1 200 bit/s
channel;
when the DTE indicates that it wishes to transmit on the 75 bit/s channel (equivalent: turning
ON CcT 120), the modem shall enable transmission on the 75 bit/s channel; and when the
DTE indicates that it no longer wishes to transmit on the 75 bit/s channel (equivalent: turning
OFF CcT 120), the modem shall disable transmission on the 75 bit/s channel.
Compliance shall be checked by the method described in annex A, clause A.3.
5.6 Response times
5.6.1 Response times of the forward channel and backward channel received line signal
detectors
The response times of the 1 200 bit/s channel and the 75 bit/s channel received line signal detectors are
the times that elapse between:
a) for the OFF to ON transition: the application of a tone corresponding to binary 1 at a level higher
than - 43 dBm to the line terminals of the modem and an indication being given to the DTE that a
carrier signal has been detected (equivalent: turning ON CcT 109).
b) for the ON to OFF transition: removal of a tone corresponding to binary 1 from, or the level falling
instantaneously to below - 48 dBm, at the line terminals of the modem and an indication being given
to the DTE that a carrier signal is no longer being detected (equivalent: turning OFF CcT 109).

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The response times of the detector shall be within the limits stated in table 2.
Compliance shall be checked by the method described in annex A, subclause A.4.1.
Table 2: Received line signal detector response times
Data OFF to ON 300 ms to 2 000 ms 10 ms to 20 ms
Channel (see note 1 below)
Signal Detector ON to OFF 5 ms to 15 ms
Backward Channel OFF to ON < 80 ms
Signal Detector ON to OFF 15 ms to 120 ms (see note 2 below)
NOTE 1: The longer range of response times is only to be used during call establishment in association
with automatic calling and answering.
NOTE 2: CCITT Recommendation V.23 [3] suggests a value of 15 ms to 80 ms.
5.6.2 Response times of the forward channel ready for sending indicator
The applicant shall state whether the ready for sending delay is either a) or b) or both of table 3, and that
information shall be included in the instruction for use.
The response times of the 1 200 bit/s channel ready for sending indicator are those given in
subclauses 5.6.2.1 to 5.6.2.3.
5.6.2.1 For modems with DTE control
The response times of the 1 200 bit/s channel ready for sending indicator are the times that elapse
between:
a) for the OFF to ON transition: a DTE indicating that it wishes to transmit in the 1 200 bit/s channel
(equivalent: turning ON CcT 105) and an indication being given to the DTE that the 1 200 bit/s
channel is ready (equivalent: turning ON CcT 106), for modes a), c) and d);
b) for the ON to OFF transition: a DTE indicating that it no longer wishes to transmit in the 1 200 bit/s
channel (equivalent: turning OFF CcT 105) and an indication being given to the DTE that the
1 200 bit/s channel is no longer ready (equivalent: turning OFF CcT 106), for modes a), c) and d).
Compliance shall be checked by the method described in annex A, subclause A.4.2.1.
5.6.2.2 For modems with control derived from the backward channel
For a modem in which control of the transmitted carrier in the 1 200 bit/s channel is controlled by the
reception of signals from the remote modem in the 75 bit/s channel, the response times of the 1 200 bit/s
channel ready for sending indicator are the times that elapse between:
a) for the OFF to ON transition: an indication to the DTE that a carrier signal has been received in the
75 bit/s channel (equivalent: turning ON CcT 122) and an indication being given to the DTE that the
1 200 bit/s channel is ready (equivalent: turning ON CcT 106);
b) for the ON to OFF transition; an indication to the DTE that a carrier signal is no longer being
received in the 75 bit/s channel (equivalent: turning OFF CcT 122) and an indication being given to
the DTE that the 1 200 bit/s channel is no longer ready (equivalent: turning OFF CcT 106).
Compliance shall be checked by the method described in annex A, subclause A.4.2.2.

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5.6.2.3 For modems which transmit carrier constantly when in the on-line state
The response times of the 1 200 bit/s channel ready for sending indicator are the times that elapse
between:
a) for the OFF to ON transition; an indication being given to the DTE that the modem is ready to
operate (equivalent: turning ON CcT 107) and an indication being given to the DTE that it is able to
transmit on the 1 200 bit/s channel (equivalent: turning ON CcT 106);
b) for the ON to OFF transition; an indication being given to the DTE that the modem is no longer
ready to operate (equivalent: turning OFF CcT 107) and an indication being given to the DTE that
the 1 200 bit/s channel is no longer ready (equivalent: turning OFF CcT 106).
The response times of the indicator shall be within the limits stated in table 3.
Compliance shall be checked by the method described in annex A, subclause A.4.2.3.
5.6.3 Response times of the backward channel ready for sending indicator
The applicant shall state whether the ready for sending delay is either a) or b) or both in table 3, and that
information shall be included in the instruction for use.
The response times of the backward channel ready for sending indicator shall be those given in
subclauses 5.6.3.1 and 5.6.3.2.
5.6.3.1 For modems with DTE control
The response times of the backward channel ready for sending indicator shall be the times that elapse
between:
a) for the OFF to ON transition: a DTE indicating that it wishes to transmit in the 75 bit/s channel
(equivalent: turning ON CcT 120) and an indication being given to the DTE that the 75 bit/s channel
is ready (equivalent: turning ON CcT 121);
b) for the ON to OFF transition: a DTE indicating that it no longer wishes to transmit in the 75 bit/s
channel (equivalent: turning OFF CcT 120) and an indication being given to the DTE that the
75 bit/s channel is no longer ready (equivalent: turning OFF CcT 121).
Compliance shall be checked by the method described in annex A, subclause A.4.3.2.
5.6.3.2 For modems with control derived from the forward channel
For a modem in which control of the transmitted carrier in the 75 bit/s channel is controlled by the
reception of signals from the remote modem in the 1 200 bit/s channel, the response times of the
backward channel ready for sending indicator are the times that elapse between:
a) for the OFF to ON transition: an indication to the DTE that a carrier signal has been received on the
1 200 bit/s channel (equivalent: turning ON CcT 109) and an indication being given to the DTE that
the 75 bit/s channel is ready (equivalent: turning ON CcT 121);
b) for the ON to OFF transition: an indication to the DTE that a carrier signal is no longer being
received on the 1 200 bit/s channel (equivalent: turning OFF CcT 109) and an indication being given
to the DTE that the 75 bit/s channel is
...