SIST EN 300 248 V1.2.1:2004

• Abstract:

  Revision to improve the safety related text following a liaison from TC Safety. Access for any apparatus intended for connection to leased circuit.

• Status: Published
• Publication Date: 30-Sep-2004
• ICS: 33.040.50 - Lines, connections and circuits
• Technical Committee: SPN - Services and Protocols for Networks
• 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 EN 300 248 V1.2.1 (2001-07) - Access and Terminals (AT); 2 048 kbit/s digital unstructured leased line (D2048U); Terminal equipment interface

Overview

SIST EN 300 248 V1.2.1:2004 specifies the terminal equipment interface requirements for connecting to a 2 048 kbit/s digital unstructured leased line (D2048U) under the Access and Terminals (AT) series. Developed by the Slovenski inštitut za standardizacijo (SIST) and harmonized with EN 300 248, this standard ensures compatibility between terminal devices and network termination points on Open Network Provision (ONP) digital leased lines operating at 2 048 kbit/s. It addresses physical and electrical interface features, with revisions enhancing alignment to updated safety-related requirements.

This standard is specifically targeted at equipment manufacturers, network operators, and service providers that require reliable, high-speed, point-to-point digital connectivity for critical applications. It is based on ITU-T Recommendation G.703 for digital interfaces, ensuring European-wide interoperability and regulatory compliance.

Key Topics

• Physical Interface Requirements: The standard outlines how terminal equipment must physically connect to the 2 048 kbit/s unstructured leased line. It prescribes the types of contacts and conductor diameters (0.4 mm to 0.6 mm) permitted for solid wire connections, ensuring secure and robust installations.
• Electrical Characteristics: Comprehensive requirements are included for output and input ports, such as:
  • Signal encoding using HDB3 (High Density Bipolar of order 3)
  • Clock accuracy at ±50 ppm
  • Impedance, input and output jitter, return loss, and signal balance
  • Immunity against reflections and tolerable longitudinal voltages, supporting resilient operation in demanding environments
• Testing Principles: Annexed test methods ensure manufacturers can verify compliance, covering signal encoding, waveform shape, clock metrics, jitter tolerance, impedance, and immunity against interference.
• Interoperability: By defining a common terminal interface, the standard supports multi-vendor compatibility within ONP frameworks and conformance with EU directives on leased lines.
• Safety and Regulatory Notes: While the main safety, overvoltage, and EMC requirements are handled by supplementary standards (such as CENELEC EN 60950), this standard references them and addresses key interaction points.

Applications

The SIST EN 300 248 V1.2.1:2004 standard is critical for:

• Telecommunications Equipment Manufacturers: Ensuring that terminal equipment is fully compatible with public and private digital leased lines at 2 048 kbit/s, supporting features such as transparent data transmission and resilience to network anomalies.
• Enterprise Network Integration: Providing businesses with reliable, standards-compliant solutions for connecting LANs, PBXs, and transmission equipment to high-capacity digital circuits, essential for voice, data, and multimedia services.
• Carrier and Service Provider Networks: Facilitating open access and seamless integration of customer-premises equipment with national and cross-border leased lines in line with Open Network Provision (ONP) requirements.
• Testing and Certification Bodies: Offering clear criteria for interface verification, ensuring interoperability and regulatory compliance.

Related Standards

• EN 300 247: Defines the connection characteristics for 2 048 kbit/s digital unstructured leased lines (D2048U), closely supporting the requirements in this standard.
• EN 300 418: Addresses the interface presentation for both structured and unstructured 2 048 kbit/s leased lines.
• ITU-T G.703: International reference for the physical and electrical characteristics of hierarchical digital interfaces.
• EN 60950 (CENELEC): Provides product safety requirements for equipment.
• Open Network Provision (ONP) Directives: Establishes the regulatory context for leased line standardization in Europe.

Adhering to SIST EN 300 248 V1.2.1:2004 helps guarantee a secure, interoperable interface for high-speed leased line connectivity, supporting mission-critical applications across the telecommunications landscape.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Dostop in terminali (AT) - Digitalni zakupljeni vodi za prenosno hitrost 2 048 kbit/s in za nestrukturirane signale (D2048U) - Vmesnik terminalske opremeAccess and Terminals (AT); 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:EN 300 248 Version 1.2.1SIST EN 300 248 V1.2.1:2004en01-oktober-2004SIST EN 300 248 V1.2.1:2004SLOVENSKI
STANDARD
ETSIEN300248V1.2.1(2001-07)EuropeanStandard(Telecommunicationsseries)AccessandTerminals(AT);2048kbit/sdigitalunstructuredleasedline(D2048U);TerminalequipmentinterfaceSIST EN 300 248 V1.2.1:2004

ETSIETSIEN300248V1.2.1(2001-07)2ReferenceREN/AT-020003Keywordsaccess,digital,leasedline,ONP,regulation,terminal,testingETSI650RoutedesLuciolesF-06921SophiaAntipolisCedex-FRANCETel.:[phone]Fax:[phone]SiretN°34862356200017-NAF742CAssociationàbutnonlucratifenregistréeàlaSous-PréfecturedeGrasse(06)N°7803/88ImportantnoticeIndividualcopiesofthepresentdocumentcanbedownloadedfrom:http://www.etsi.orgThepresentdocumentmaybemadeavailableinmorethanoneelectronicversionorinprint.Inanycaseofexistingorperceiveddifferenceincontentsbetweensuchversions,thereferenceversionisthePortableDocumentFormat(PDF).Incaseofdispute,thereferenceshallbetheprintingonETSIprintersofthePDFversionkeptonaspecificnetworkdrivewithinETSISecretariat.Usersofthepresentdocumentshouldbeawarethatthedocumentmaybesubjecttorevisionorchangeofstatus.InformationonthecurrentstatusofthisandotherETSIdocumentsisavailableathttp://www.etsi.org/tb/status/Ifyoufinderrorsinthepresentdocument,sendyourcommentto:[e-mail]opartmaybereproducedexceptasauthorizedbywrittenpermission.Thecopyrightandtheforegoingrestrictionextendtoreproductioninallmedia.©EuropeanTelecommunicationsStandardsInstitute2001.Allrightsreserved.SIST EN 300 248 V1.2.1:2004

ETSIETSIEN300248V1.2.1(2001-07)3ContentsIntellectualPropertyRights.5Foreword.5Introduction.61Scope.72References.73Definitions.74Abbreviations.85Requirements.85.1Physicalcharacteristics.85.1.1Hardwiredconnection.95.1.2Alternativemeansofconnection.95.2Electricalcharacteristics.95.2.1Outputport.95.2.1.1Signalcoding.95.2.1.2Waveformshape.95.2.1.3Clockaccuracy.105.2.1.4Impedancetowardsground.115.2.1.5Outputjitter.115.2.1.6Outputreturnloss.115.2.1.7Outputsignalbalance.115.2.2Inputport.115.2.2.1Signalcoding.115.2.2.2Inputreturnloss.125.2.2.3Inputlosstolerance.125.2.2.4Immunityagainstreflections.125.2.2.5Tolerablelongitudinalvoltages.125.2.2.6Impedancetowardsground.125.2.2.7Inputjittertolerance.135.2.2.8Inputclocktolerance.135.3Safety.145.4Overvoltage.145.5Electro-magneticcompatibility.14AnnexA(normative):Testmethods.15A.1General.15A.1.1Additionalinformationtosupportthetest.15A.1.2Equipmentconnection.15A.2Testmethods.16A.2.1Signalcodingatoutputport.16A.2.2Waveformshapeatoutputport.16A.2.3Clockaccuracyattheoutputport.17A.2.4Returnlossatinputport.18A.2.5Inputlosstoleranceandimmunityagainstreflections.18A.2.6TolerablelongitudinalvoltageandHDB3inputcoding.20A.2.7Impedancetowardsground.21A.2.8Jitter.22AnnexB(normative):DefinitionofHDB3code.24B.1General.24B.2Definition.24SIST EN 300 248 V1.2.1:2004

ETSIETSIEN300248V1.2.1(2001-07)4AnnexC(informative):Bibliography.25History.26SIST EN 300 248 V1.2.1:2004

ETSIETSIEN300248V1.2.1(2001-07)5IntellectualPropertyRightsIPRsessentialorpotentiallyessentialtothepresentdocumentmayhavebeendeclaredtoETSI.TheinformationpertainingtotheseessentialIPRs,ifany,ispubliclyavailableforETSImembersandnon-members,andcanbefoundinETSISR000314:"IntellectualPropertyRights(IPRs);Essential,orpotentiallyEssential,IPRsnotifiedtoETSIinrespectofETSIstandards",whichisavailablefromtheETSISecretariat.LatestupdatesareavailableontheETSIWebserver(http://www.etsi.org/ipr).PursuanttotheETSIIPRPolicy,noinvestigation,includingIPRsearches,hasbeencarriedoutbyETSI.NoguaranteecanbegivenastotheexistenceofotherIPRsnotreferencedinETSISR000314(ortheupdatesontheETSIWebserver)whichare,ormaybe,ormaybecome,essentialtothepresentdocument.ForewordThisEuropeanStandard(Telecommunicationsseries)hasbeenproducedbyETSITechnicalCommitteeAccessandTerminals(AT).ThepresentdocumentresultsfromamandatefromtheEuropeanCommissiontoprovideEuropeanstandardsforthesupportoftheDirectiveonOpenNetworkProvision(ONP)ofleasedlines(92/44/EEC).Therearetwootherstandardsdirectlyrelatedtothepresentdocument:-EN300418:"AccessandTerminals(AT);2048kbit/sdigitalunstructuredandstructuredleasedlines(D2048UandD2048S);Networkinterfacepresentation";-EN300247:"AccessandTerminals(AT);2048kbit/sdigitalunstructuredleaseline(D2048U);Connectioncharacteristics".ThepresentdocumentisbasedoninformationfromITU-TRecommendationsandETSIpublicationsandtherelevantdocumentsarequotedwhereappropriate.NationaltranspositiondatesDateofadoptionofthisEN:29June2001DateoflatestannouncementofthisEN(doa):30September2001DateoflatestpublicationofnewNationalStandardorendorsementofthisEN(dop/e):31March2002DateofwithdrawalofanyconflictingNationalStandard(dow):31March2002SIST EN 300 248 V1.2.1:2004

ETSIETSIEN300248V1.2.1(2001-07)6IntroductionTheCouncilDirectiveontheapplicationofOpenNetworkProvision(ONP)toleasedlines(92/44/EEC),concernstheharmonizationofconditionsforopenandefficientaccessto,anduseof,theleasedlinesprovidedonpublictelecommunicationsnetworksandtheavailabilitythroughouttheCommunity(EC)ofaminimumsetofleasedlineswithharmonizedtechnicalcharacteristics.TheconsequenceoftheDirectiveisthatTelecommunicationsOrganizationswithintheECshallmakeavailableasetofleasedlinesbetweenpointsinthesecountrieswithspecifiedconnectioncharacteristicsandspecifiedinterfaces.EN300166andITU-TRecommendationG.703[1]wereusedasthebasisfortheterminalinterface.Twocategories(voluntaryandregulatory)ofstandardwereusedfortheinterfacesofterminalequipmentdesignedforconnectiontotheONPleasedlines.TechnicalBasisforRegulations(TBRs)gavetheearlieressentialrequirementsundertheDirective91/263/EEC,laterreplacedby98/13/EC,forattachmenttotheleasedlines,whereasothervoluntarystandards(ETSsorENs)gavethefulltechnicalspecificationsfortheseinterfaces.Thisdocument,whichisbasedonanearlierETS,belongstothesecondcategory.TherequirementsofTBR12areasubsetofthepresentdocument.Thepresentversionofthepresentdocumenthasbeenproducedtointroducesomenecessarychanges.SIST EN 300 248 V1.2.1:2004

ETSIETSIEN300248V1.2.1(2001-07)71ScopeThepresentdocumentspecifiesthephysicalandelectricalcharacteristics(exceptsafety,overvoltageandEMCaspects)andcorrespondingtestprinciplesforaterminalequipmentinterfaceforconnectiontothenetworkterminationpointsofONP2048kbit/sdigitalunstructuredleasedlinesusing120Ωinterfaces.ThepresentdocumentistoensurethattheinterfaceoftheterminalequipmentiscompatiblewiththeONP2048kbit/sdigitalunstructuredleasedline.Itisapplicabletoallinterfacesdesignedforconnectiontotheleasedline,howeverinthecasesofapparatusthatcarriesaparticularservice,ofcomplexapparatusandofapparatusinprivatenetworks,otherrequirementsmayapplyinadditiontothepresentdocument.CustomerpremiseswiringandinstallationbetweentheterminalequipmentandtheNetworkTerminationPoint(NTP)areoutsidethescopeofthepresentdocument.2ReferencesThefollowingdocumentscontainprovisionswhich,throughreferenceinthistext,constituteprovisionsofthepresentdocument.• Referencesareeitherspecific(identifiedbydateofpublication,editionnumber,versionnumber,etc.)ornon-specific.• Foraspecificreference,subsequentrevisionsdonotapply.• Foranon-specificreference,thelatestversionapplies.[1]ITU-TRecommendationG.703(1998):"Physical/electricalcharacteristicsofhierarchicaldigitalinterfaces".[2]ITU-TRecommendationO.151(1992):"Errorperformancemeasuringequipmentoperatingattheprimaryrateandabove".3DefinitionsForthepurposesofthepresentdocument,thefollowingtermsanddefinitionsapply:Leasedlines:telecommunicationsfacilitiesprovidedbyapublictelecommunicationsnetworkthatprovidedefinedtransmissioncharacteristicsbetweennetworkterminationpointsandthatdonotincludeswitchingfunctionsthattheusercancontrol,(e.g.on-demandswitching)NetworkTerminationPoint(NTP):allphysicalconnectionsandtheirtechnicalaccessspecificationswhichformpartofthepublictelecommunicationsnetworkandarenecessaryforaccessto,andefficientcommunicationthrough,thatpublicnetworkTerminalEquipment(TE):equipmentintendedtobeconnectedtothepublictelecommunicationsnetwork,i.e.:a)tobeconnecteddirectlytotheterminationofapublictelecommunicationsnetwork;orb)tointerworkwithapublictelecommunicationsnetworkbeingconnecteddirectlyorindirectlytotheterminationofapublictelecommunicationsnetwork,inordertosend,process,orreceiveinformation.SIST EN 300 248 V1.2.1:2004

ETSIETSIEN300248V1.2.1(2001-07)84AbbreviationsForthepurposesofthepresentdocument,thefollowingabbreviationsapply:D2048U2048kbit/sdigitalunstructuredONPleasedlineDCDirectCurrentEMCElectro-MagneticCompatibilityHDB3HighDensityBipolarcodeoforder3(seeannexB)NTPNetworkTerminationPointONPOpenNetworkProvisionppmpartspermillionPRBS(215-1)PseudoRandomBitSequence(asdefinedinclause2.1ofITU-TRecommendationO.151[2])rmsrootmeansquareRXReceive(asignalinputateithertheterminalequipmentinterfaceorthetestequipment)SDHSynchronousDigitalHierarchyTETerminalEquipmentTXTransmit(asignaloutputateithertheterminalequipmentinterfaceorthetestequipment)UIUnitInterval5RequirementsThe2048kbit/sunstructuredleasedlineprovidesabidirectionalpoint-to-pointdigitalleasedlinewithausablebitrateof2048kbit/swheretimingisnotprovidedfromthenetwork.Theprovisionofcircuittimingistheresponsibilityoftheuser.Nostructuringofthedataisprovidedbythenetworkandanystructuringistheresponsibilityoftheuser.5.1PhysicalcharacteristicsCurrentlynostandardizedconnectorisreadilyavailable.Consequently,theonlymethodofconnectionthatcanbespecifiedinthepresentdocumentistheuseofsolidconductorsof0,4mmto0,6mm.ThepresentdocumentrequirestheTEtobecapableofpresentingeitherapointfortheattachmentofunterminatedsolidconductors,orsolidconductorsthemselves(seeclause5.1.1).ItisarequirementthatsuchaconnectionmethodbeavailabletobeprovidedforusewiththeTEifnecessary.Inordertoallowconnectiontobemadeusingothermethods(e.g.connectors),theTEispermittedtobesuppliedwithaconnectionmethodsuitableforusewiththosemethods(seeclause5.1.2).NOTE1:Thefollowingareexamplesofarrangementsthatcomplywiththerequirements.Thelistbelowshouldnotberegardedasanexhaustivelistofallpermittedarrangements:a)acord,permanentlyconnectedtotheterminalequipmentatoneendandunterminatedattheotherend,withwiresthataresolidconductorswithdiametersintherange0,4mmto0,6mm;b)acord,connectedviaaplugandsockettotheterminalequipmentatoneendandunterminatedattheotherend,withwiresthataresolidconductorswithdiametersintherange0,4mmto0,6mm;c)aninsulationdisplacementconnector,designedtoacceptwireswithsolidconductorswithdiametersintherange0,4mmto0,6mm,butwithnocord;d)ascrewconnector,designedtoacceptwireswithsolidconductorswithdiametersintherange0,4mmto0,6mm,butwithnocord;e)thearrangementinb)plusoneormoreadditionalalternativecordswiththesameplugorsocketarrangementattheterminalendandanyplugorsocketattheotherend;f)thearrangementinc)ord)plusoneormorecordssuitableforconnectiontotheterminalequipmentatoneendandanyplugorsocketattheotherend.Thetransmitpairistheoutputfromtheterminalequipmentinterface.Thereceivepairistheinputtotheterminalequipmentinterface,asshowninfigure1.Wheretheterms"output"and"input"areusedwithoutqualificationinthepresentdocument,theyrefertotheterminalequipmentinterface.SIST EN 300 248 V1.2.1:2004

ETSIETSIEN300248V1.2.1(2001-07)9Figure1NOTE2:TheuseofashieldedcordorcablemaybenecessarytomeetradiationandimmunityrequirementsdefinedinElectroMagneticCompatibility(EMC)standards.5.1.1HardwiredconnectionRequirement:Theterminalequipmentshallprovide:a)asetofconnectioncontacts(e.g.aninsulationdisplacementconnectororascrewterminalblock)towhichsolidwireconductorswithdiametersintherange0,4mmto0,6mmmaybeconnected;orb)awiringarrangementconnectedbyanymeanstotheterminalequipment,withunterminatedsolidwireconductorswithdiametersintherange0,4mmto0,6mmattheenddistantfromtheterminalequipment.Test:Thereisnotest.Allsubsequenttestsarecarriedoutviathespecifiedconnectionmethod.5.1.2AlternativemeansofconnectionAnyalternativemeansofconnectionmaybeprovidedinadditiontotheconnectionarrangementsunderclause5.1.1.5.2Electricalcharacteristics5.2.1Outputport5.2.1.1SignalcodingRequirement:CodingofthedigitalsignaltransmittedattheoutputportshallbeinaccordancewithHighDensityBipolarcodeoforder3(HDB3)encodingrules(seeannexB).Test:ThetestshallbeconductedaccordingtoannexA,clauseA.2.1.5.2.1.2WaveformshapeRequirement:Thepulseattheoutputportshallcomplywiththerequirementsgivenintable1andfigure2,basedonITU-TRecommendationG.703[1].Test:ThetestshallbeconductedaccordingtoannexA,clauseA.2.2.Table1:WaveformshapeatoutputportPulseshape(nominallyrectangular)Allmarksofavalidsignalshallconformwiththemask(seefigure2)irrespectiveofthepolarity.ThevalueVcorrespondstothenominalpeakvoltageofamark.Testloadimpedance120Ω non-reactiveNominalpeakvoltageVofamark3VPeakvoltageofaspace0±0,3VNominalpulsewidth244nsRatiooftheamplitudesofpositiveandnegativepulsesatthecentreofthepulseinterval0,95to1,05Ratioofthewidthsofpositiveandnegativepulsesatthenominalhalfamplitude0,95to1,05INPUTINPUTOUTPUTOUTPUTTXNETWORKINTERFACETXTERMINALEQUIPMENTSIST EN 300 248 V1.2.1:2004

ETSIETSIEN300248V1.2.1(2001-07)10269ns194ns(244-50)=100%50%0%10%10%10%10%20%244ns219ns(244-25)488ns(244+244)Nominalpulse20%20%10%10%(244+25)Figure2:Pulsemaskfor2048kbit/spulse5.2.1.3ClockaccuracyRequirement:WhereaTerminalEquipment(TE)hasaninternalclock,intheabsenceofanyexternalreferencesignaltiming,theoutputportshallhaveabitrateof2048kbit/s±50ppm.Test:ThetestshallbeconductedaccordingtoannexA,clauseA.2.3.SIST EN 300 248 V1.2.1:2004

ETSIETSIEN300248V1.2.1(2001-07)115.2.1.4ImpedancetowardsgroundRequirement:Wheretheterminalequipmenthasaground,theimpedancetowardsgroundoftheoutputportshallbegreaterthan1000Ωforfrequenciesintherange10Hzto1MHzwhenmeasuredwithasinusoidaltestvoltageof2Vrms.Forthepurposeofthisrequirement,groundshallbetheterminalequipm
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