1、E!:; N ICA 3qOY583 0066377 T75 ce ETR 004 August 1990 UDC: 621.395 Key words: Business Telecommunications (BT); Overall transmission plan aspects of a private branch network for voice connections with access to the public network ETSI European Telecommunications Standards Institute ETSI Secretariat:
2、 B.P.152 , F - 06561 Vaibonne Cedex . France TP. + 33 92 94 42 00 TF. + 33 93 65 47 16 Tx. 47 00 40 F 0 ETSI 1990. m 3404583 00bb198 901 m Foreword ETSI Technical Reports (ETRs) are informative documents resulting from ETSI studies which are not appropriate for European Telecommunication Standard (E
3、TS) or Interim - European Telecommunication Standard (I-ETS) status. An ETR may be used to publish material which is either of an informative nature, relating to the use or application of ETSs or I-ETSs, or which is immature and not yet suitable for formal adoption as an ETS or I-ETS. This ETR has b
4、een produced by the Business Telecommunications (BT) Technical Committee of the European Telecommunications Standards Institute (ETSI). 3404583 0066379 848 Page 1 ETR 004:1990 Table of Contents 1 General 1.1 Scope and Introduction 1.2 Principal Recommendation 2 General Guidance and Information on Tr
5、ansmission Parameters 2.0 General 2.1 Loudness Ratings 2.1.1 General Information 2.1.2 LRs in the National System 2.1.3 Planning with LRs 2.1.4 LRs of Telephone Sets 2.1.5 2.2 Sidetone 2.2.1 General Information 2.2.2 STMR 2.2.3 LSTR 2.2.4 Planning of a National System comprising a PBN Implications f
6、or Impedance Matching in the 2-wire Parts of the Network 2.3 Propagation Time 2.3.1 General Information 2.3.2 Limits for a Connection 2.3.3 Sources of Delay 2.3.4 2.4 Talker Echo 2.4.1 General Information 2.4.2 Talker Echo Limits 2.4.3 Electrical Echo Control 2.4.4 Acoustic Echo Control 2.4.5 Echo l
7、oss of PBNs Allocation of Delay to the PBN 2.5 Stability 2.6 2-wire-4-wire-2-wire Loop 2.6.1 General Information 2.6.2 Nuiaber of 4-wire Loops 2.6.3 Attenuation of 4-wire Loops 2.7 Quantizing Distortion Units 2.7.1 General Information 2.7.2 Sources of Quantizing Distortion 2.7.3 Apportionment of qdu
8、s 2.8 Noise 2.8.1 General Information 2.8.2 Treatment of noise withhin a PBN 2.9 Attenuation Distortion 3404583 00bb200 3T = Pago 2 ETR 004:lSSO 3 Specific Recommendations 3.1 General Remarks 3.2 Digital Access with a wholly digital Call Path within the ISDN/PSTN 3.2.1 Definition and Reference Conne
9、ction 3.2.2 Number of qdu 3.2.3 Echo Control 3.2.3.1 Propagation Time 3.2.3.2 Echo Loss of the PBN seen from the NCP 3.2.3.3 Echo Loss wholly within the PBN 3.2.4 Stability 3.2.5 Loudness Ratings 3.3 3.3.1 Definition and Reference Connection 3.3.2 Number of qdu 3.3.3 Echo Control 3.3.3.1 Propagation
10、 Time 3.3.3.2 Echo Loss of the PBN seen from the NCP 3.3.3.3 Echo Loss wholly within the PBN or PSTN access 3.3.4 Stability 3.3.5 Loudness Ratings Digital Access with a mixed analogue and digital Call Path within the ISDN/PSTN 3.4 3.4.1 Definition and Reference Connection 3.4.2 Number of qdu 3.4.3 E
11、cho Control 3.4.4 Stability 3.4.5 Loudness Ratings Analogue Access to the PSTN with a wholly digital Call Path within the PSTN 3.5 Analogue Access to the PSTN with a mixed analogue and digital Call Path within the PSTN 3.5.1 Definition and Reference Connection 3.5.2 Number of qdu 3.5.3 Echo Control
12、3.5.4 Stability 3.5.5 Loudness Ratings Annex A Abbreviations Annex B Tenns and Definitions Appendix Note regarding Deutsche Bundespost TELEKOMS long-term echo loss objectives for PBNs Page 3 ETR 004:1990 Overall Transmission Plan Aspects of a Private Branch Network for Voice Connections with Access
13、to the Public Network 1 General 1.1 Scope and Introduction This Technical Report is a Framework Document which is intended for use by Administrations, and public and private network operators. It deals with the transmission planning of Private Branch Networks (PBNs) which send or receive speech tele
14、phone calls to or from Public Switched Telephone Networks (PSTNs) or Public Integrated Services Digital Networks (ISDNs). It recognises the overall responsibility of administrations for ensuring that the quality of national communications is consistent with international quality objectives. This Tec
15、hnical Report is divided into three main Sections together with two Annexes. The three Sections are: Section 1: Scope, introduction and principal recommendation, Section 2: General guidance and information on transmission parameters, Section 3: Specific Recommendations. In addition, Annex A lists th
16、e abbreviations and Annex B the terms and definitions used in this Technical Report. This guidance and general information is given for the benefit of administrations who are drawing up national rules for private network transmission and for the benefit of private network operators who are planning
17、their networks. Public networks within Europe contain a mixture of analogue and digital equipment and there are significant differences in the design of the analogue networks in different countries (e.g. different loudness levels). In addition, although the public networks will eventually be very si
18、milar when they are fully digital, the conversion from analogue to digital will be carried out in different ways and at different times in different countries. During this conversion process, it may be possible to increase the impairnient allowances given to private networks and the greatest possibl
19、e flexibility in this respect is desirable. For these reasons it is impracticable to establish a European Telecommunications Standard for private networks where the call paths in the public network contain analogue sections. However, the Recommendations in Section 3 for the case where the call path
20、in the public network is fully digital may be suitable as the basis for an ETS. m 3404583 OObb202 Lb2 m Pago 4 ETR 004:1990 The Recommendations in Section 3 relate only to calls which pass through a public switched network to an international switching centre. In the case of other calls (e.g. nation
21、al calls) it may be possible for the impairment allowances for private networks to be increased. The approach followed is to specify the performance of a private network at the point or points where it is connected to a public network. This approach may also be used for private networks that include
22、 international private leased circuits, provided that the performance at the connection point is maintained. However, the approach to more complex topologies using international private leased circuits is for further study. The transmission planning in this Technical Report is valid, in principle, f
23、or analogue private automatic branch exchanges (PABXs), digital PABXs and PABXs with ISDNServices (ISPBXs). In this Recommendation only the term PABX is used. The transmission characteristics of digital PABXs can be found in 4 the following ETCS: T/TE 10-01 T/TE 10-02 T/TE 10-03 Transmission Charact
24、eristics of digital PABXs Transmission Characteristics of 2-wire analogue Interfaces of a digital PABX Transmission Characteristics of 4-wire analogue Interfaces of a digital PABX T/TE 10-04 Section 2 of this Technical Report concerning the general transmission parameters provides information about
25、the relevant CCITT Recommendations of the G.lOO series and the P series which should be taken into account in the transmission planning of a telephone network. Unless otherwise stated, all references to CCITT Recommendations refer to CCITTs Blue Books (1989). This Section gives guidance and backgrou
26、nd information for administrations and public network operators, private service providers, manufacturers and users. Transmission Characteristics at digital Interfaces of a digital PABX Transmission planning aspects of the speech service in the European mobile system (GSM PLMN) are covered by CEPT R
27、ecommendations GSM 03.50 and T/TM 03.12. The successful interworking of a mobile system and cordless telephones forming part of a PBN is under study. 3404583 00bb203 OT = Paga 5 ETR 004:lSSO 1.2 Principal Recommendation Administrations are recommended to introduce, within their legal and contractual
28、 arrangements for telecommunications, rules for the planning of PBNs which send or receive speech telephone calls to or from a PSTN or an ISDN. Such rules should be consistent with the Recommendations set out in Section 3 of this Technical Report, and Administrations should draw, as appropriate, upo
29、n the guidance and information in Section 2 when framing them. When an administration is framing technical rules for the public international interconnection of PBNs it should assume .that the planning of PBNs in other European countries complies with rules framed in accordance with the Recommendati
30、ons in Section 3. RLR = + 2 dB with the volume control in the nominal position. Draft ETS T/TE 04-15 (Candidate for NET 33) states the transmission characteristics of a European ISDN digifal telephone. The values of SLR and RLR are: SLR = + 7 dB; RLR = + 3 dB 2.1.4.3 Loudspeaker telephones For hands
31、-free telephones using loudspeakers the SLR and RLR should be measured and computed using the methods given in CCITT Recommendation P.34 Section 6 (Note). Note: Further work is required to develop a practical test method using, for instance, CCITT Recommendation P.50. 2.1.4.4 Headset telephones For
32、headset telephones the SLR and RLR should be measured and computed using the methods given in CCITT Recommendation P.38. Study is continuing in CCITT SG XII on other types of earpieces. 2.1.4.5 System-specific telephones For system-specific telephones the SLR and RLR should be measured and computed
33、using one of the methods given in CCITT Recommendations (P.31, P.34 Section 6 or P.38) appropriate to the type of acoustic interface, ie, handset, microphone/loudspeaker or headset. The values of SLR and RLR to be used for planning purposes are the nominal values declared by the supplier to and from
34、 a reference point declared by the supplier. Note: The reference point will, in general, be treated within the PBX or equivalent system to which the telephone is specific. 3404583 00bb214 984 W Paga 16 ETR 004:1990 2.1.5 Planning of a National System comprising a PBN The network planning guidance gi
35、ven in this Standard is based on the use of handset telephones. However, this mode of network planning also allows loudspeaker and headset telephones to be connected. As shown in Table 2.1/1, the following maximum LRs have been defined for national systems including PBNs connected to the PSTN by mea
36、ns of 2-wire analogue lines: SLEm, = 16.5 dB Ri,%, = 12.5 dB This results in a maximum OLR of 29 dB. However, these maximum values should only be used in exceptional cases. This is shown in Figure 2,1/4a. The division of the LRs is a national matter. However for a digital connection to the ISDN (Fig
37、ure 2.1/4b) the overall value for the national system will be completly determined by the PBN values. Hence the SLR and RLR value for the PBN should ( meet the long term CCITT objectives as given in Table 2.1/1. This could be achieved using the configuration in Figure 2.1/4b where a digital telephon
38、e with the European values 7 dB and 3 dB is connected directly to the ISDN via a PABX. In the mixed analogue/digital PBN a digital PABX with digital telephone sets can be connected to the PSTN by means of 2-wire lines. In preparation of a future ISDN connection it is advisable that these digital tel
39、ephone sets have the same LR values as defined in NET 33. In the case of an analogue 2-wire connection to the PSTN, the objective is at least to meet the CCITT Recommendation for the maximum value (preferably the short-term maximum value) of the national system as given in Table 2.1/1. The example i
40、n Figure 2.1/4c shows how this may be achieved taking into account the minimum loss and maximum gain in the K2-interface of the digital PABX. = 3404583 00bb215 Bi10 d Pago 17 ETR 004:lSSO / I I l I J 1 I I RLR = 12.5 dB I RLR I I 3dB I I Figure 2.1/4 Examples of SLR and RLR of the national system m
41、3404583 OObb2lb 757 m I I i I I II Pagm 18 ETR O4:1990 L / I I I i Figure 2.1/5 and Table 2.1/4 show planning values for the national system in a number of countries. I I Local System RLR I ! I, I I I b-, National System RLR = 12.5dB ,-i I I Figure 2.1/5 Configuration for which the planning values o
42、f Table 2.1/4 are applicable 3404583 0066237 693 Page 19 ETR 004:1990 Country Austria Denmark Finland France FRG Greece Italy Nether1 Norway Spain nds Sweden (Note Switzerland U.K. T in dB 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.0 0.0 0.0 0.0 1.0 R in dB 7.0 6.0 7.0 7.0 7.0 7.0 7.0 5.0 7.0 7.0 7.0 6.0 5.0 7.5
43、 3.0 2.5 7.0 4.5 Local System (max 1 SLR in dB 11.5 9.0 14.0 9.5 RLR in dB 0.5 -2.0 3.0 -1.5 Note: The value of R includes 2 dB digitally implemented loss. Table 2.1/4 Examples of planning values of the national system as part of an international connection For purely national connections the value
44、of R is 5 dB. m 3404583 00bb2L8 52T m Pago 20 ETR 004:1990 In a case of an analogue telephone set the division of the SLR and RLR of the telephone set and the R and T pads are of national competence. However the objective should be to achieve the same overall value as for the digital telephone set,
45、as shown in Figure 2.1/6. I 1 I SLR i dB dig. I I LE PC ISC I I RLR 1 I I r 3dB I Figure 2.1/6 SLR and RLR values of an analogue telephone conected to the ISDN = 3404583 00bb2L 466 m Page 21 ETR 004:1990 2.2 Sidetone 2.2.1 General Information TWO effects of sidetone have to be taken into account: -
46、Sidetone Masking Rating, STMR (Talkers sidetone) and - Listeners Sidetone Rating, LSTR STMR is the loudness loss between a users mouth and his ear (earphone) via the electrical sidetone path. LSTR is the loudness loss between a Hoth-type room noise source and the users ear (earphone) via the electri
47、cal sidetone path. For analogue telephone sets both are determined by the grade of conformity between the sidetone balance impedance inside the telephone set and the line impedance. For digital telephone sets both are determined by the electrical characteristics of the artificial sidetone path betwe
48、en the sending and receiving direction and possible, low-delay reflections at the other end of the connection. To reach satisfactory sidetone characteristics for the most critical case of long subscriber lines with low receiving loudness, the analogue telephone sets are usually equipped with capacit
49、ive complex sidetone balancing networks, similar to the image impedance of unloaded subscriber cables. (To provide these characteristics on short extension lines in digital PABXs as well, these PABXs should have a capacitive complex input impedance). An alternative method, sometimes used at exchanges with resistive input impedances, is to employ telephone sets with a variable sidetone balance impedance Zso controlled by the feeding current. Thus, on short extension lines Zso is made to emulate the actual resistive exchange impedance. The artificial sidetone path of digital
