SIST ETS 300 248 E1:2004

• Abstract:

  Candidate access CTR for any apparatus intended for connection to this form of leased circuit

• Status: Published
• Publication Date: 30-Sep-2004
• ICS: 33.040.50 - Lines, connections and circuits
• Technical Committee: BTC - Business telecommunications
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Oct-2004
• Due Date: 01-Oct-2004
• Completion Date: 01-Oct-2004
• Mandate: T-147-2
• Ref Project: ETSI ETS 300 248 ed.1 (1993-10) - Business Telecommunications (BT); Open Network Provision (ONP) technical requirements; 2 048 kbit/s digital unstructured leased line (D2048U) Terminal equipment interface

SIST ETS 300 248 E1:2004 is the Slovenian adoption of ETS 300 248 Edition 1, a European Telecommunications Standard from ETSI. It defines the terminal equipment interface for the 2 048 kbit/s digital unstructured leased line (D2048U), including the physical and electrical characteristics and the test principles used to check them. In practice, it is the document for designers, manufacturers and test labs that need equipment to connect correctly to the network termination point of ONP leased lines.

What does SIST ETS 300 248 E1:2004 specify?

SIST ETS 300 248 E1:2004 specifies the interface for terminal equipment that connects to ONP 2 048 kbit/s digital unstructured leased lines using 120 W interfaces. It is not written for regulatory approval purposes, and customer premises wiring between the terminal equipment and the Network Termination Point (NTP) is outside its scope.

The document is organized as follows:

Annex	What it covers
Annex A	Normative test methods for the interface requirements
Annex B	Normative definition of the HDB3 code
Annex C	Informative bibliography

The main body covers scope, normative references, definitions, symbols and abbreviations, and the requirement set for physical characteristics, electrical characteristics, safety, overvoltage protection and EMC.

What are the key requirements of SIST ETS 300 248 E1:2004?

SIST ETS 300 248 E1:2004 focuses on how the interface is connected, how the 2 048 kbit/s signal is coded and shaped, and how the equipment behaves under timing, noise, safety and surge conditions. The practical value is straightforward: if the equipment meets these points, it is designed to interwork with the leased line interface without relying on the network to provide timing or framing.

Physical interface

Clause 5.1 requires an 8-contact plug of the type in ISO/IEC 10173, with receive on contacts 1 and 2, transmit on contacts 4 and 5, shield reference on contacts 3 and 6, and contacts 7 and 8 unused. That gives manufacturers a fixed connector and pinout, so the interface can be wired and tested consistently.

Clause 5.1 also allows an alternative connection method, mainly for hardwired presentations using insulation displacement terminals. In practice, this gives installers and equipment builders a second way to present the leased line when a plug-and-cord arrangement is not used.

Signal coding and timing

Clause 5.2.1.1 requires High Density Bipolar code of order 3 (HDB3) at the output port, and Clause 5.2.2.1 requires the input port to decode HDB3 without errors. This means the terminal equipment has to transmit and accept the line code used on the leased line, not just raw bits.

Clause 5.2.1.2 sets the output pulse shape, nominal peak level and pulse balance, based on CCITT Recommendation G.703. Clause 5.2.1.3 requires an internal clock, when used, to stay at 2 048 kbit/s ± 50 ppm. Together, these requirements control the actual waveform and timing that reaches the line.

Clause 5.2.2.3 to 5.2.2.8 cover input loss tolerance, immunity against reflections, longitudinal voltage tolerance, jitter tolerance and clock tolerance. In practice, the receiver must keep decoding correctly even when the cable is lossy, mismatched, noisy or timing is not ideal.

Safety, protection and surges

Clause 5.3 requires accessible parts of the interface to comply with SELV conditions, and Clause 5.3.2 limits touch current to 0,25 mA. That matters for user protection, especially in mains-powered equipment.

Clause 5.4 sets the overvoltage protection tests. The equipment has to survive common-mode and transverse surges, mains simulation, and impulse transfer tests, and still operate properly afterward without resets, hardware changes or reloading protected data. This tells buyers and labs how the interface should hold up under electrical stress.

What terms does SIST ETS 300 248 E1:2004 define?

• Leased lines - Telecommunications facilities provided by a public network with defined transmission characteristics between network termination points and no user-controlled switching.
• Network Termination Point (NTP) - The physical network access point and its technical specifications at the boundary of the public telecommunications network.
• Terminal Equipment (TE) - Equipment intended to connect to the public telecommunications network to send, process or receive information.
• Safety Extra-Low Voltage (SELV) - A secondary circuit designed so accessible voltages remain within a safe value under normal and single-fault conditions.
• HDB3 - High Density Bipolar code of order 3, the modified AMI code used for the line signal.
• D2048U - The 2 048 kbit/s digital unstructured ONP leased line covered by this interface.
• PRBS(2^15-1) - A pseudo random bit sequence used as the test pattern in Annex A.
• EMC - Electro-Magnetic Compatibility, the area that covers emissions and immunity behaviour.

Who uses SIST ETS 300 248 E1:2004?

SIST ETS 300 248 E1:2004 is used by terminal equipment manufacturers, telecom hardware designers, conformance test laboratories and quality teams that need to verify interface compatibility. It is also relevant to buyers and network planners who specify equipment for connection to ONP leased lines, because it defines the interface behaviour that the product has to match.

Which standards are used with SIST ETS 300 248 E1:2004?

• CCITT Recommendation G.703 - Provides the physical and electrical basis for the interface, including pulse shape and return-loss related parameters.
• CCITT Recommendation O.151 - Supplies the PRBS definition used in the interference and jitter tests.
• EN 60950 - Provides the safety requirements for accessible parts treated as SELV.
• ETS 300 046-2 - Provides the touch-current test basis used for safety assessment.
• ETS 300 046-3 - Provides the overvoltage protection test methods used in Clause 5.4.
• ISO/IEC 10173 - Defines the 8-contact connector used for the physical interface.
• ETS 300 246 - Covers interface presentation for the same D2048U leased line family.
• ETS 300 247 - Covers connection characteristics for the same D2048U leased line family.
• ETS 300 166 - Is cited as a related physical/electrical basis for hierarchical digital interfaces.

What does the SIST ETS 300 248 E1:2004 document contain?

The document includes the connector assignment table, the pulse mask figure, the return-loss table and the jitter limit table used to check compliance. Annex A gives test setups and pass/fail methods for coding, waveform shape, clock accuracy, return loss, loss tolerance, reflections, longitudinal voltage, impedance towards ground and jitter. Annex B gives the HDB3 coding rule used throughout the standard. Annex C lists background references, including the related Directives and ETSI publications.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Business Telecommunications (BT); Open Network Provision (ONP) technical requirements; 2 048 kbit/s digital unstructured leased line (D2048U) Terminal equipment interface33.040.50Vodi, zveze in tokokrogiLines, connections and circuitsICS:Ta slovenski standard je istoveten z:ETS 300 248 Edition 1SIST ETS 300 248 E1:2004en01-oktober-2004SIST ETS 300 248 E1:2004SLOVENSKI
STANDARD
EUROPEANETS 300 248TELECOMMUNICATIONOctober 1993STANDARDSource: ETSI TC-BTReference: DE/BT-02020ICS:33.020Key words:ONP, leased lines, 2048UBusiness Telecommunications (BT);Open Network Provision (ONP) technical requirements;2 048 kbit/s digital unstructured leased line (D2048U)Terminal equipment interfaceETSIEuropean 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: [e-mail].: [phone] - Fax: [phone]Copyright 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 1993. All rights reserved.SIST ETS 300 248 E1:2004

Page 2ETS 300 248: October 1993Whilst 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 Standards Approval Dept." at the address shown on the title page.SIST ETS 300 248 E1:2004

Page 3ETS 300 248: October 1993ContentsForeword.5Introduction.51Scope.72Normative references.73Definitions.74Symbols and abbreviations.85Requirements.95.1Physical characteristics.95.2Electrical characteristics.95.2.1Output port.95.2.1.1Signal coding.95.2.1.2Waveform shape.105.2.1.3Clock accuracy.115.2.1.4Impedance towards ground.125.2.1.5Output jitter.125.2.1.6Output return loss.125.2.1.7Output signal balance.125.2.2Input port.125.2.2.1Signal coding.125.2.2.2Input return loss.135.2.2.3Input loss tolerance.135.2.2.4Immunity against reflections.135.2.2.5Tolerable longitudinal voltages.135.2.2.6Impedance towards ground.135.2.2.7Input jitter tolerance.145.2.2.8Input clock tolerance.145.3Safety.155.3.1General requirements.155.3.2Touch current.155.4Overvoltage protection.155.4.1Surge simulation, common mode.155.4.2Surge simulation, transverse mode between transmit and receive pairs.165.4.3Mains simulation, common mode.165.4.4Mains simulation, transverse mode.165.4.5Impulse transfer from mains, common mode.165.4.6Impulse transfer from mains, transverse mode.165.4.7Conversion of common mode to transverse mode.165.5Electro-magnetic compatibility.16Annex A (normative):Test methods.17A.1General.17A.1.1Additional information to support the test.17A.1.2Equipment connection.17A.2Test methods.18A.2.1Signal coding at output port.18A.2.2Waveform shape at output port.18SIST ETS 300 248 E1:2004

Page 4ETS 300 248: October 1993A.2.3Clock accuracy at the output port.19A.2.4Return loss at input port.20A.2.5Input loss tolerance and immunity against reflections.20A.2.6Tolerable longitudinal voltage and HDB3 input coding.22A.2.7Impedance towards ground.23A.2.8Jitter.24Annex B (normative):Definition of HDB3 code.26B.1General.26B.2Definition.26Annex C (informative):Bibliography.27History.28SIST ETS 300 248 E1:2004

Page 5ETS 300 248: October 1993ForewordThis European Telecommunication Standard (ETS) has been produced by the BusinessTelecommunications (BT) Technical Committee of the European Telecommunications Standards Institute(ETSI).This ETS results from a mandate from the Commission of the European Community (CEC) to provideharmonised standards for the support of the Directive on Open Network Provision (ONP) of leased lines(92/44/EEC).There are two other standards directly related to this ETS:ETS 300 246: "Open Network Provision (ONP) technical requirements; 2 048 kbit/s digitalunstructured leased line (D2048U), Interface presentation";ETS 300 247: "Open Network Provision (ONP) technical requirements; 2 048 kbit/s digitalunstructured leased line (D2048U), Connection characteristics".This ETS is based on information from CCITT Recommendations and ETSI publications and the relevantdocuments are quoted where appropriate.IntroductionThe Council Directive on the application of Open Network Provision (ONP) to leased lines (92/44/EEC),concerns the harmonisation of conditions for open and efficient access to, and use of, the leased linesprovided on public telecommunications networks and the availability throughout the Community (EEC) of aminimum set of leased lines with harmonised technical characteristics.The consequence of the Directive is that Telecommunications Organisations within the EEC shall makeavailable a set of leased lines between points in these countries with specified connection characteristicsand specified interfaces.Two classes of standard will be used for the interfaces of terminal equipment designed for connection tothe ONP leased lines. European Telecommunication Standards (ETSs), which are voluntary, give the fulltechnical specifications for these interfaces, whereas Technical Basis for Regulations (TBRs) give theessential requirements under the Second Phase Directive (91/263/EEC) for attachment to the leased lines.This standard, which is an ETS, belongs to the first category. The TBR (TBR 12) is a subset of thiscorresponding ETS.ETS 300 166 and CCITT Recommendation G.703 are used as the basis for the terminal interface.SIST ETS 300 248 E1:2004

Page 6ETS 300 248: October 1993Blank pageSIST ETS 300 248 E1:2004

Page 7ETS 300 248: October 19931ScopeThis ETS specifies the full physical and electrical characteristics and corresponding test principles for aterminal equipment interface for connection to the network termination points of ONP 2 048 kbit/s digitalunstructured leased lines using 120 W interfaces.This ETS is not intended for regulatory purposes. A separate TBR (TBR 12) covers the essentialrequirements for attachment under the Second Phase Directive (91/263/EEC).This ETS is to ensure that the interface of the terminal equipment is compatible with the ONP 2 048 kbit/sdigital unstructured leased line. It is applicable to all interfaces designed for connection to the leased line,however in the cases of apparatus that carries a particular service, of complex apparatus and of apparatusin private networks, other ETSs may apply in addition to this ETS.Customer premises wiring and installation between the terminal equipment and the Network TerminationPoint (NTP) are outside the scope of this ETS.2Normative referencesThis ETS incorporates by dated or undated reference, provisions from other publications. These normativereferences are cited at the appropriate places in the text and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this ETSonly when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies.[1]CCITT Recommendation G.703 (1991): "Physical/electrical characteristics ofhierarchical digital interfaces".[2]CCITT Recommendation O.151 (1988): "Error performance measuringequipment for digital systems at the primary rate and above".[3]EN 60950 (1992): "Safety of information technology equipment includingelectrical business equipment".[4]ETS 300 046-2 (1992): "Integrated Services Digital Network (ISDN); Primaryrate access - safety and protection, Part 2: Interface Ia - safety".[5]ETS 300 046-3 (1992): "Integrated Services Digital Network (ISDN); Primaryrate access - safety and protection, Part 3: Interface Ia - protection".[6]ISO/IEC 10173 (1991): "Information technology - Integrated Services DigitalNetwork (ISDN) primary access connector at reference points S and T".NOTE:This ETS also contains a number of informative references which have been included toindicate the sources from which various material has been derived, hence they do nothave an associated normative reference number. Details of these publications are givenin Annex C. In some cases the same publication may have been referenced in both anormative and an informative manner.3DefinitionsFor the purposes of this ETS, the following definitions apply:Leased lines: the telecommunications facilities provided by a public telecommunications network thatprovide defined transmission characteristics between network termination points and that do not includeswitching functions that the user can control, (e.g. on-demand switching).SIST ETS 300 248 E1:2004

Page 8ETS 300 248: October 1993Network Termination Point (NTP): all physical connections and their technical access specificationswhich form part of the public telecommunications network and are necessary for access to, and efficientcommunication through, that public network.Safety Extra-Low Voltage (SELV) circuit: a secondary circuit which is so designed and protected thatunder normal and single fault conditions the voltage between any two accessible parts, or between oneaccessible part and the equipment protective earthing terminal for a class I equipment, does not exceed asafe value (subclause 1.2.8.5 of EN 60950 [3]).Terminal Equipment (TE): equipment intended to be connected to the public telecommunications network,i.e.:a)to be connected directly to the termination of a public telecommunications network; orb)to interwork with a public telecommunications network being connected directly orindirectly to the termination of a public telecommunications network,in order to send, process, or receive information.4Symbols and abbreviationsFor the purposes of this ETS, the following abbreviations apply:D2048U2 048 kbit/s digital unstructured ONP leased lineDCDirect CurrentEMCElectro-Magnetic CompatibilityHDB3High Density Bipolar code of order 3 (see Annex B)ONPOpen Network ProvisionNTPNetwork Termination Pointppmparts per millionPRBS(215-1)Pseudo Random Bit Sequence (as defined in § 2.1 of CCITT RecommendationO.151 [2])RXReceive (a signal input at either the terminal equipment interface or the testequipment)rmsroot mean squareSELVSafety Extra-Low VoltageSDHSynchronous Digital HierarchyTETerminal EquipmentTXTransmit (a signal output at either the terminal equipment interface or the testequipment)UIUnit IntervalSIST ETS 300 248 E1:2004

Page 9ETS 300 248: October 19935RequirementsThe 2 048 kbit/s unstructured leased line provides a bidirectional point-to-point digital leased line with ausable bit rate of 2 048 kbit/s where timing is not provided from the network. The provision of circuit timingis the responsibility of the user. No structuring of the data is provided by the network and any structuring isthe responsibility of the user.5.1Physical characteristicsRequirement: The terminal equipment shall provide an 8-contact plug of the type specified inISO/IEC 10173 [6] with contact assignments as specified in table 1. In addition, the terminal equipmentmay provide an alternative method of connection.NOTE 1:The use of a shielded cord or cable may be necessary to meet radiation and immunityrequirements defined in Electro-Magnetic Compatibility (EMC) standards.NOTE 2:The alternative connection method is primarily for the purpose of permitting hardwiredpresentations of the leased line using insulation displacement terminals and wire withsolid conductors having diameters in the range 0,4 to 0,6 mm.Test: There shall be a visual inspection that the plug is of the correct type. The contact assignments aretested indirectly through the tests in Annex A.Table 1: Contact assignmentContactTerminal interface1 & 2Receive pair3Shield reference point4 & 5Transmit pair6Shield reference point7Unused8UnusedNOTE 1:The transmit pair is the output from the terminal equipment interface. The receive pair is theinput to the terminal equipment interface, as shown in figure 1. Where the terms "output" and"input" are used without qualification in this standard, they refer to the terminal equipmentinterface.NOTE 2:For connection of the shield, or shields, to the common reference point at the NTP contacts 3and 6 shall be used.ÉÍÍÍÍÍÍÍÍÍÍÍÍ» OUTPUT
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OUTPUT ÈÍÍÍÍÍÍÍÍÍÍÍͼFigure 15.2Electrical characteristics5.2.1Output port5.2.1.1Signal codingRequirement: Coding of the digital signal transmitted at the output port shall be in accordance with HighDensity Bipolar code of order 3 (HDB3) encoding rules (see Annex B).Test: The test shall be conducted according to Annex A, subclause A.2.1.SIST ETS 300 248 E1:2004

Page 10ETS 300 248: October 19935.2.1.2Waveform shapeRequirement: The pulse at the output port shall comply with the requirements given in table 2 and figure 2,based on CCITT Recommendation G.703 [1].Test: The test shall be conducted according to Annex A, subclause A.2.2.Table 2: Waveform shape at output portPulse shapeAll marks of a valid signal shall conform(nominally rectangular)with the mask (see figure 2) irrespectiveof the polarity. The value V correspondsto the nominal peak voltage of a mark.Test load impedance120 W non-reactiveNominal peak voltage V of a mark3 VPeak voltage of a space0 ± 0,3 VNominal pulse width244 nsRatio of the amplitudes of positive and negative 0,95 to 1,05pulses at the centre of the pulse intervalRatio of the widths of positive and negative 0,95 to 1,05pulses at the nominal half amplitudeSIST ETS 300 248 E1:2004

Page 11ETS 300 248: October 1993269 ns194 ns(244 - 50)V=100%50%0%10%10%10%10%20%244 ns219 ns(244 - 25)488 ns(244 + 244)Nominal pulse20%20%10%10%(244 + 25)Figure 2: Pulse mask for 2 048 kbit/s pulse5.2.1.3Clock accuracyRequirement: Where a Terminal Equipment (TE) has an internal clock, in the absence of any externalreference signal timing, the output port shall have a bit rate of 2 048 kbit/s ± 50 ppm.Test: The test shall be conducted according to Annex A, subclause A.2.3.SIST ETS 300 248 E1:2004

Page 12ETS 300 248: October 19935.2.1.4Impedance towards groundRequirement: Where the terminal equipment has a ground, the impedance towards ground of the outputport shall be greater than 1 000 W for frequencies in the range 10 Hz to 1 MHz when measured with asinusoidal test voltage of 2 V rms. For the purpose of this requirement, ground shall be the terminalequipment common reference point or the equipment test reference point.NOTE:This requirement is included to allow transformerless implementations.Test: The test shall be conducted according to Annex A, subclause A.2.7.5.2.1.5Output jitterRequirement: The peak-to-peak output jitter shall not exceed the limits of table 3 when measured with abandpass filter with first order linear cut-off with the defined cut-off frequencies. For the purpose of testing,any signal input from which the output timing is derived shall be provided with the maximum tolerable inputjitter, and with the maximum tolerable input frequency deviation, as specified by the manufacturer.Where the output timing of the terminal equipment is taken from the leased line, the input to the terminalequipment shall be provided with components of sinusoidal jitter at points on the curve of figure 3 andtable 5 (see subclause 5.2.2.7 below).NOTE:A separate requirement for output jitter at frequencies in the range 4 Hz to 40 Hz is notrequired because this frequency band is covered sufficiently by the first order linearfilter which produces 20 dB attenuation at 4 Hz.Table 3: Maximum output jitterMeasurement filter bandwidthOutput jitterLower cut-offUpper cut-offUI peak-to-peak(high pass)(low pass)(maximum)40 Hz100 kHz0,11 UITest: The test shall be conducted according to Annex A, subclause A.2.8.5.2.1.6Output return lossThere are no requirements for output return loss under this ETS.NOTE:A requirement for output return loss may be added to this ETS when appropriatespecifications become available.5.2.1.7Output signal balanceThere are no requirements for output signal balance under this ETS.NOTE:The effects of the output signal imbalance are covered under the EMC Directive(89/336/EEC).5.2.2Input port5.2.2.1Signal codingRequirement: The input port shall correctly decode without errors HDB3 encoded signals in accordancewith HDB3 encoding rules (see Annex B).Test: The test shall be conducted according to Annex A, subclause A.2.6.SIST ETS 300 248 E1:2004

Page 13ETS 300 248: October 19935.2.2.2Input return lossRequirement: The input return loss with respect to 120 W at the interface shall be greater than or equal tothe values given in table 4 taken from § 6.3.3 of CCITT Recommendation G.703 [1].Table 4: Input port minimum return lossFrequency rangeReturn loss51 kHzto102 kHz12 dB102 kHzto2 048 kHz18 dB2 048 kHzto3 072 kHz14 dBTest: The test shall be conducted according to Annex A, subclause A.2.4.5.2.2.3Input loss toleranceRequirement: The input port shall correctly decode without errors a 2 048 kbit/s signal as defined insubclauses 5.2.1.1 and 5.2.1.2 above but modified by a cable or artificial cable with the followingcharacteristics:a)attenuation that follows a ´f law with values throughout the range 0 to 6 dB at 1 024 kHz; andb)characteristic impedance of 120 W with a tolerance of ± 20 % in the frequency range from 200 kHzup to, but not including, 1 MHz, and ± 10 % at 1 MHz.Test: The test shall be according to Annex A, subclause A.2.5.5.2.2.4Immunity against reflectionsRequirement: When a signal comprising a combination of a normal signal and an interfering signal isapplied to the input port, via an artificial cable with a loss in the range 0 dB to 6 dB at 1 MHz, no errorsshall result due to the interfering signal.The normal signal shall be a signal encoded according to HDB3, shaped according to the mask of figure 2and with a binary content in accordance with a Pseudo Random Bit Sequence as defined in § 2.1 of CCITTRecommendation O.151 [2] (PRBS(215-1)).The interfering signal shall be the same as the normal signal except that the level shall be attenuated by18 dB, the bit rate shall be within 2 048 kbit/s ± 50 ppm and not synchronised to the normal signal.Test: The test shall be conducted according to Annex A, subclause A.2.5.5.2.2.5Tolerable longitudinal voltagesRequirement: The receiver shall operate without errors with any input signal in the presence of alongitudinal voltage of magnitude 2 V rms over the frequency range 10 Hz to 30 MHz.NOTE:This requirement is included to allow transformerless implementations.Test: The test shall be conducted according to Annex A, subclause A.2.6.5.2.2.6Impedance towards groundRequirement: Where the terminal equipment has a ground, the impedance towards ground of the inputport shall be greater than 1 000 W for frequencies in the range 10 Hz to 1 MHz when measured with asinusoidal test voltage of 2 V rms. For the purpose of this requirement, ground shall be the terminalequipment common reference point or the equipment test reference point.NOTE:This requirement is included to allow transformerless implementations.SIST ETS 300 248 E1:2004

Page 14ETS 300 248: October 1993Test: The test shall be conducted according to Annex A, subclause A.2.7.5.2.2.7Input jitter toleranceRequirement: The terminal equipment shall tolerate at its input port the maximum input jitter as shown intable 5 and figure 3.NOTE:Term
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