1、 ETSI ES 201 235-4 V1.3.1 (2006-03)ETSI Standard Access and Terminals (AT);Specification of Dual-Tone Multi-Frequency (DTMF) Transmitters and Receivers;Part 4: Transmitters and Receivers for use inTerminal Equipment for end-to-end signallingETSI ETSI ES 201 235-4 V1.3.1 (2006-03) 2 Reference RES/AT-
2、010128 Keywords DTMF, PSTN, signalling ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice Individu
3、al copies of the present document can be downloaded from: http:/www.etsi.org The present document may be made available in more than one electronic version or in print. In any case of existing or perceived difference in contents between such versions, the reference version is the Portable Document F
4、ormat (PDF). In case of dispute, the reference shall be the printing on ETSI printers of the PDF version kept on a specific network drive within ETSI Secretariat. Users of the present document should be aware that the document may be subject to revision or change of status. Information on the curren
5、t status of this and other ETSI documents is available at http:/portal.etsi.org/tb/status/status.asp If you find errors in the present document, please send your comment to one of the following services: http:/portal.etsi.org/chaircor/ETSI_support.asp Copyright Notification No part may be reproduced
6、 except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2006. All rights reserved. DECTTM, PLUGTESTSTM and UMTSTM are Trade Marks of ETSI registered for the benefit of its Members. T
7、IPHONTMand the TIPHON logo are Trade Marks currently being registered by ETSI for the benefit of its Members. 3GPPTM is a Trade Mark of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. ETSI ETSI ES 201 235-4 V1.3.1 (2006-03) 3 Contents Intellectual Property Rig
8、hts4 Foreword.4 1 Scope 5 2 References 5 3 Definitions, symbols and abbreviations .5 3.1 Definitions5 3.2 Symbols6 3.3 Abbreviations .6 4 The receiver6 4.1 Area of application .6 4.2 Operate and non-operate requirements.7 4.2.1 Signal condition requirements 7 4.2.1.1 Valid signal for an analogue rec
9、eiver7 4.2.1.2 Invalid signal for an analogue receiver .7 4.2.1.3 Valid signal for a digital receiver8 4.2.1.4 Invalid signal for a digital receiver .8 4.2.2 Digit Recognition Condition (DRC) requirements .9 4.3 Speech immunity performance.10 5 The transmitter .10 6 Electrical characteristics.10 Ann
10、ex A (normative): Speech immunity test signal11 Annex B (informative): Example test signal 13 Annex C (informative): Bibliography.14 History 15 ETSI ETSI ES 201 235-4 V1.3.1 (2006-03) 4 Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declare
11、d to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is
12、 available from the ETSI Secretariat. Latest updates are available on the ETSI Web server (http:/webapp.etsi.org/IPR/home.asp). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not ref
13、erenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to the present document. Foreword This ETSI Standard (ES) has been produced by ETSI Technical Committee Access and Terminals (AT). The present document is part 4 of a multi-part delivera
14、ble covering the Specification of Dual-tone Multi-Frequency (DTMF) Transmitters and Receivers, as identified below: Part 1: “General“; Part 2: “Transmitters“; Part 3: “Receivers“; Part 4: “Transmitters and Receivers for use in Terminal Equipment for end-to-end signalling“. ETSI ETSI ES 201 235-4 V1.
15、3.1 (2006-03) 5 1 Scope The present document specifies the Dual-tone Multi-Frequency (DTMF) signalling system. The various parts of this multi-part deliverable provide a complete set of requirements for applications intending to use DTMF signalling. The present document is intended to provide the le
16、vel of detail that will enable manufacturers of telecommunications equipment incorporating DTMF signalling, to design the equipment such that it facilitates highly reliable signalling. This should not be taken to imply that any DTMF signalling system that fails to meet all the criteria described in
17、the present document will not provide reliable signalling. The present document is not intended to be used for the definition of regulated interfaces. The present document covers the requirements for the DTMF transmitter and receiver for the case of DTMF signalling during an established call from TE
18、 to TE. 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. References are either specific (identified by date of publication and/or edition number or version number) or non-specific. For a specific reference,
19、subsequent revisions do not apply. For a non-specific reference, the latest version applies. Referenced documents which are not found to be publicly available in the expected location might be found at http:/docbox.etsi.org/Reference. 1 ETSI ES 201 235 (all parts): “Access and Terminals (AT); Specif
20、ication of Dual-tone Multi-Frequency (DTMF) Transmitters and Receivers“. 2 ETSI I-ETS 300 245-1: “Integrated Services Digital Network (ISDN); Technical characteristics of telephony terminals; Part 1: General“. 3 Definitions, symbols and abbreviations 3.1 Definitions For the purposes of the present d
21、ocument, the following terms and definitions apply: Digit Recognition Condition (DRC): output state of the receiver in response to a valid input signal when the relevant signal condition and time requirements are satisfied high group: signalling frequencies, which have nominal values of 1 209 Hz, 1
22、336 Hz, 1 477 Hz and 1 633 Hz low group: signalling frequencies, which have nominal values of 697 Hz, 770 Hz, 852 Hz and 941 Hz Valid Signal Condition (VSC): state of the line at the input of the receiver when: 1) one of the frequency combinations specified in ES 201 235-1 is present; and 2) the fre
23、quencies are within the tolerances specified in clauses 4.2.1.1 and 4.2.1.3 item a); and ETSI ETSI ES 201 235-4 V1.3.1 (2006-03) 6 3) the signalling levels are within the range of acceptable levels specified in clauses 4.2.1.1 and 4.2.1.3 items b) and c); and 4) any unwanted frequencies are within t
24、he limits as specified in clauses 4.2.1.1 and 4.2.1.3 item i to iii) of ES 201 235-4 3.2 Symbols For the purposes of the present document, the following symbols apply: The Star on the standard 3x4 keypad array, also known as the asterisk # The Square on the standard 3x4 keypad array, also known as t
25、he hash, sharp, or number sign (“pound“ in the USA) dBm0 Power level expressed in decibels relative to 1 mW in a 0 dBr level reference point dBV Absolute voltage level expressed in decibels relative to 1 volt 3.3 Abbreviations For the purposes of the present document, the following abbreviations app
26、ly: CLI Calling Line Identification DRC Digit Recognition ConditionDTMF Dual-tone Multi-Frequency HPF High Pass Filter LPF Low Pass Filter R Rectifiers SPF Single Pole Filter STF Single Tone Filter TC Threshold Comparator TE Terminal Equipment VSC Valid Signal Condition 4 The receiver 4.1 Area of ap
27、plication The present document deals with the receiver or receiver function for DTMF signalling incorporated into TE. This implies that the receiver needs to be capable of dealing with both the frequency related attenuation as a result of two local loops and the exchanges and interconnecting trunk c
28、ircuits as well as any changes in frequency that might be introduced by the equipment used by the network provider(s). The receiver shall respond to signals received over a network from a distant transmitter conforming to clause 5. The receiver shall be equipped to recognize the sixteen signals desi
29、gnated 0 to 9, *, #, A, B, C and D. The system may be utilized with only, ten discrete signals, in which case the signals designated 0 to 9, should be used; or with twelve discrete signals, in which case the signals 0 to 9, *, # should be used. In the interests of system security, the receiver may b
30、e conditioned to recognize only specific digits from the complete set of sixteen digits. NOTE: The principal uses of the receiver as dealt with in the present document are expected to be: (a) in TE receiving signals from a remote TE e.g. remote control of an answering/recording machine; (b) in TE re
31、ceiving signals from equipment such as an CLI based server. This may be connected so as not to introduce the extra attenuation of the second local connection. ETSI ETSI ES 201 235-4 V1.3.1 (2006-03) 7 4.2 Operate and non-operate requirements 4.2.1 Signal condition requirements The following clauses
32、define the conditions under which the DTMF function shall decide to indicate or not indicate to the host equipment the digit that is represented by a received signal. There will be some conditions that fall into neither of these two states and the designer of the DTMF function can make their own dec
33、ision whether such signals are best considered valid or not valid. 4.2.1.1 Valid signal for an analogue receiver The received DTMF signal shall be detected as valid when only two of the signalling frequencies are present at the receiver input one from the high group and one from the low group which
34、meet the conditions described in items a) to c): a) each of these signalling frequencies is within (1,5 % +2 Hz) of the nominal value; and b) the level of each of these two signalling frequencies is within the range -43 dBV to -3 dBV; and c) the difference in level of these two signalling frequencie
35、s is not more than 10 dB. The received DTMF signal shall also be detected as valid even if accompanied by other frequency components not exceeding: i) in the frequency range 300 Hz to 480 Hz a level of -43 dBV; ii) in the frequency range 480 Hz to 3 400 Hz a total voltage level of 20 dB below the le
36、vel of the low group signalling frequency; iii) at frequencies over 3 400 Hz, an individual signal level of -36 dBV at 3 400 Hz rising at 6 dB per octave to a level of +10 dBV. NOTE 1: In item b), a dynamic range of 40 dB is specified to take into account tolerances in the send levels of the DTMF tr
37、ansmitter and also variations in attenuation found in connections via various networks. NOTE 2: It is pointed out that some equipment may require protection to cover interference from specified sources, e.g. meter pulses. This may be in addition to that specified in item iii). 4.2.1.2 Invalid signal
38、 for an analogue receiver The received DTMF signal shall be considered as invalid if any of the conditions given in items a) to c) are satisfied at the receiver input: a) the signal levels are correct for valid signals but more than two of the signalling frequencies are present; or b) the level of t
39、he signalling frequency in the low group is less than -48 dBV; or c) the level of the signalling frequency in the high group is less than -48 dBV. As an aid to the understanding of clauses 4.2.1.1 and 4.2.1.2, table 1 is given. ETSI ETSI ES 201 235-4 V1.3.1 (2006-03) 8 Table 1: Signal condition requ
40、irements Signal condition Frequency deviation (Hz) Signal level x (dBV) Signal level difference y (dB) Unwanted frequencies z (dBV) Is valid (1,5 % + 2) -43 x -3 y (1,5 % + 2) -48 x -3 y 10 z Invalid x (1,5 % + 2) -40 x -4 y 8 z Not valid x 40 ms Shall cease Not VSC 40 ms May exist 20 ms VSC 40 ms M
41、ay cease 20 ms Not VSC 40 ms Shall not exist VSC 20 ms Shall not cease Not VSC 20 ms * or optionally a different digit recognition condition Legend: VSC The continuous existence of a valid signal condition. Not VSC The continuous non-existence of valid signal condition. DRC The existence of digit re
42、cognition condition. Not DRC The non-existence of digit recognition condition. ETSI ETSI ES 201 235-4 V1.3.1 (2006-03) 104.3 Speech immunity performance The receiver should not perform more than 46 false operations per 100 speech hours at a long-term active speech level of -13 dBV at analogue receiv
43、ers and -13 dBm0 for digital receivers. A speech hour is defined as a total duration of one hour when speech (in both directions) may, be present, that is when the circuit is seized and the call established (conversation condition). NOTE 1: In addition to the simulation of signals by speech entering
44、 via the microphone, mis-operation may also be caused by disturbances preventing detection of valid signals and/or splitting them into double digits. The design of a receiver with very high rejection efficiency against signal imitation might lead to an intolerable increase in the number of blockings
45、. The general design aim should be to limit both types of mis-operation (imitation and blocking) to a total level not exceeding one per 10 000 digits dialled. NOTE 2: The duration of 100 hours has been given as the recommended test duration but sufficient accuracy can be achieved by using 10 speech
46、hours, which can be further reduced by applying the time compression procedure described in annex A. For test of the speech immunity performance or for comparison between different receivers the test specified in annex A can be used. 5 The transmitter The analogue transmitters for use in terminal eq
47、uipment for end-to-end signalling shall comply with the requirements as defined in part 2 of this multi-part deliverable. The digital transmitters for use in terminal equipment for end-to-end signalling shall comply with the requirements as defined in part 2 of this multi-part deliverable with the f
48、ollowing amendment: The sending levels for each frequency, measured selectively, shall be -15 dBm0 with the tolerance of 2 dB. For this end-to-end signalling option in ISDN telephony terminals, see I-ETS 300 245-1 2. 6 Electrical characteristics NOTE: The electrical characteristics of the interface
49、will be determined by the apparatus into which the function of the DTMF receiver or transmitter has been incorporated. ETSI ETSI ES 201 235-4 V1.3.1 (2006-03) 11Annex A (normative): Speech immunity test signal The speech immunity performance of the receiver is tested by means of a standardized common test signal. The common standardized test signal is a collection of speech “bursts“ which simulate characters on a reference receiver when applied at the NTP. The reference unprotected receiver is defined in figure A.1 and in the
