I E C 61 6-3 -1 ® Edition 3.0 201 7-05 I N TE RN ATI ON AL S TAN D ARD colour i n sid e C on n e ctors for el ectri cal an d e l ectron i c e q u i pm e n t – P rod u ct req u i re m e n ts – P art -1 4: D e tai l s peci fi cati on for -way, s h i el d ed free an d fi xed n e ctors for IEC 61 076-3-1 04:201 7-05(en) d ata tran s m i s s i on s wi th fre q u e n ci es u p to 0 M H z T H I S P U B L I C AT I O N I S C O P YRI G H T P RO T E C T E D C o p yri g h t © I E C , G e n e v a , S wi tz e rl a n d All rights reserved Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or IEC's member National Committee in the country of the requester If you have any questions about I EC copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or your local I EC member National Committee for further information IEC Central Office 3, rue de Varembé CH-1 21 Geneva 20 Switzerland Tel.: +41 22 91 02 1 Fax: +41 22 91 03 00 info@iec.ch www.iec.ch Ab ou t th e I E C The I nternational Electrotechnical Commission (I EC) is the leading global organization that prepares and publishes I nternational Standards for all electrical, electronic and related technologies Ab o u t I E C p u b l i ca ti o n s The technical content of IEC publications is kept under constant review by the IEC Please make sure that you have the latest edition, a corrigenda or an amendment might have been published I E C Catal og u e - webstore i ec ch /catal og u e The stand-alone application for consulting the entire bibliographical information on IEC International Standards, Technical Specifications, Technical Reports and other documents Available for PC, Mac OS, Android Tablets and iPad I E C pu bl i cati on s s earch - www i ec ch /search pu b The advanced search enables to find IEC publications by a variety of criteria (reference number, text, technical committee,…) It also gives information on projects, replaced and withdrawn publications E l ectroped i a - www el ectroped i a org The world's leading online dictionary of electronic and electrical terms containing 20 000 terms and definitions in English and French, with equivalent terms in additional languages Also known as the International Electrotechnical Vocabulary (IEV) online I E C G l os sary - s td i ec ch /g l oss ary 65 000 electrotechnical terminology entries in English and French extracted from the Terms and Definitions clause of IEC publications issued since 2002 Some entries have been collected from earlier publications of IEC TC 37, 77, 86 and CISPR I E C J u st Pu bl i s h ed - webstore i ec ch /j u stpu bl i sh ed Stay up to date on all new IEC publications Just Published details all new publications released Available online and also once a month by email I E C C u stom er S ervi ce C en tre - webstore i ec ch /csc If you wish to give us your feedback on this publication or need further assistance, please contact the Customer Service Centre: csc@iec.ch I E C 61 6-3 -1 ® Edition 3.0 201 7-05 I N TE RN ATI ON AL S TAN D ARD colour i n sid e C on n ectors for el ectri cal an d e l ectron i c eq u i pm en t – P rod u ct req u i rem en ts – P art -1 4: D etai l s peci fi cati on for -way, s h i el d ed free an d fi xed n e ctors for d ata tran s m i s s i on s wi th fre q u en ci es u p to 0 M H z INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 33.1 20.1 ISBN 978-2-8322-4362-6 Warn i n g ! M ake s u re th a t you ob tai n ed th i s p u b l i cati on from an au th ori zed d i stri b u tor ® Registered trademark of the International Electrotechnical Commission –2– I EC 61 076-3-1 04: 201 © I EC 201 CONTENTS FOREWORD I NTRODUCTI ON 1 Scope 1 Norm ative references 1 Technical inform ation 3 Terms and definitions 3 Levels of compatibility I nterchangeability level 2 I nterm ateabilty 3 I nteroperability 3 Groups of related connectors 4 Classification into climate categories 5 Clearance and creepage distances Current carrying capacity Marking General Performance marking Dim ensional inform ation General I som etric views and comm on features General 2 Fixed connector variant 01 (cable outlet) Fixed connector variant 02, (printed circuit board outlet) 20 4 Free connector variant 03 (4-pair plug) 21 Free connector variant 04 (2-pair plug) 25 Free connector variant 05 (1 -pair plug) 27 Terminations 30 General 30 Referenced solderless termination types 30 3 Non-referenced termination types 31 4 Solder terminations 31 4 Mounting inform ation 31 4 General 31 4 Mounting information for fixed connectors 31 4 Mounting inform ation for free connectors 31 Gauges 31 Sizing gauges and retention force gauges; m echanical function, engaging/separating/insertion/withdrawal force 31 Mechanical function, engaging/separating/insertion/withdrawal force gauges 38 Test panels 38 Characteristics 39 General 39 Pin and pair grouping assignm ent 39 Climatic categories 39 Electrical characteristics 40 Creepage and clearance distances 40 Voltage proof 40 I EC 61 076-3-1 04: 201 © I EC 201 –3– Current carrying capacity 40 4 I nitial contact and shield resistance 41 5 I nput to output resistance 41 I nput to output resistance unbalance 41 I nsulation resistance 42 5 Transmission characteristics 42 5 General 42 5 I nsertion loss 42 5 Return loss 42 5 Propagation delay 43 5 Delay skew 43 5 NEXT loss 43 5 Power sum N EXT loss (for inform ation onl y) 43 5 FEXT loss 44 5 Power sum FEXT loss (for information onl y) 44 5 Transverse conversion loss 45 5 1 Transverse conversion transfer loss 45 5 Power sum alien (exogenous) N EXT loss 46 5 Power sum alien (exogenous) FEXT loss 46 5 Coupling attenuation 47 5 Transfer im pedance 47 Mechanical characteristics 47 Test schedule 48 General 48 Test procedures and measuring methods 48 Preconditioning 48 Wiring and mounting of specimens 48 Wiring 48 Mounting 48 Arrangem ent for contact resistance m easurem ent and procedure 49 4 Arrangem ent for d ynamic stress tests (test phase CP1 ) 49 Test schedules 50 General 50 Basic (m inimum) test schedule 50 Full test schedule 50 Annex A (normative) Gauging procedure 59 A Fixed connectors 59 A Free connectors 59 Annex B (normative) Locking device mechanical operation – test procedure and requirem ents 60 B Object 60 B Preparation of the specimens 60 B Test method 60 B Final measurements 60 Annex C (norm ative) Plug and outlet interoperability qualification 61 C Object 61 C Test equipment 61 C Test procedure 62 Annex D (norm ative) General requirem ents for the m easurement set-up 63 –4– I EC 61 076-3-1 04: 201 © I EC 201 D Test instrum entation 63 D Coaxial cables and test leads for network anal ysers 63 D Measurem ent precautions 63 D Balun requirements 64 D Reference components for calibration 65 D Reference loads for calibration 65 D Reference cables for calibration 65 D Termination loads for term ination of conductor pairs 65 D Termination of screens 66 D Test specim en and reference planes 67 Annex E (normative) I nsertion loss 68 E Object 68 E Test method 68 E Test set up 68 E Procedure 68 E 4.1 Calibration 68 E 4.2 Measurement 68 E Test report 69 E Accuracy 69 Annex F (norm ative) Return loss 70 F.1 Object 70 F.2 Test method 70 F.3 Test set-up 70 F.4 Procedure 70 F Calibration 70 F Measurement 70 F.5 Test report 70 F.6 Accuracy 70 Annex G (norm ative) Near end cross talk (N EXT) 72 G.1 Object 72 G.2 Test method 72 G.3 Test set-up 72 G.4 Procedure 73 G Calibration 73 G Establishm ent of noise floor 73 G Measurement 73 G.5 Test report 74 G.6 Accuracy 74 Annex H (norm ative) Far end cross talk (FEXT) 75 H Object 75 H Test method 75 H Test set-up 75 H Procedure 76 H Calibration 76 H Establishm ent of noise floor 76 H Measurem ent 76 H Test report 77 H Accuracy 77 I EC 61 076-3-1 04: 201 © I EC 201 –5– Annex I (normative) Transverse Conversion Loss ( TCL ) and Transverse Conversion Transfer Loss ( TCTL ) 78 I.1 Object 78 I.2 Test method 78 I.3 Test set-up 78 I.4 Procedure 79 I Calibration 79 I Noise floor 79 I Measurement 80 I.5 Test report 80 I.6 Accuracy 80 Annex J (norm ative) Termination of balun 81 J Termination of balun with low return loss for common m ode 81 J Centre tap connected to ground 81 J Centre tap open 81 Bibliograph y 83 Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure – I sometric view of cable and PCB fixed connectors – I sometric view showing free connector for 4, and pair – Variant 01 drawing – Variant 01 drawing – Variant 02 drawing 20 – Variant 03 drawing 21 – Variant 03 drawing 22 – Variant 03 drawing 24 – Variant 04 drawing 25 – Variant 04 drawing 26 1 – Variant 05 drawing 27 – Variant 05 drawing 28 – Variant 05 drawing 29 – Fixed connector location "Go" gauge 32 – Fixed connector location "No-Go" gauge 32 – Fixed connector size "Go" gauge 33 – Fixed connector size "N o-Go" gauge 34 – Free connector location "Go" gauge 35 – Free connector location "N o-Go" gauge 36 20 – Free connector size "Go" gauge 37 21 – Free connector size "No-Go" gauge 38 22 – Fixed connector panel 39 23 – Schem atic diagram of fixed connector 39 24 – Connector de-rating curve 41 25 – Arrangement for contact resistance measurem ent 49 26 – Arrangement for d ynam ic stress 50 C.1 – Precision test fixtures (covers) 61 D.1 – 80 ° h ybrid used as a balun 64 –6– I EC 61 076-3-1 04: 201 © I EC 201 Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure D.2 – Calibration of reference loads 65 D.3 – Resistor load 66 D.4 – Definition of reference planes 67 E – Calibration 68 E – Measuring set-up 69 G – N EXT measurem ent differential mode onl y term inations 72 G – N EXT measurem ent differential and common m ode terminations 73 H – FEXT measurement differential m ode onl y terminations 75 H – FEXT m easurement differential and common mode term inations 76 I – TCL measurem ent 78 I – TCTL m easurem ent 79 J – Balanced attenuator for balun centre tap grounded 81 J – Balanced attenuator for balun centre tap open 82 Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table Table – Variant 01 drawing dimensions – Variant 01 drawing dimensions – Variant 02 drawing dim ensions 20 – Variant 03 drawing dimensions 22 – Variant 03 drawing dimensions 23 – Variant 03 drawing dimensions 24 – Variant 04 drawing dimensions 25 – Variant 04 drawing dimensions 26 – Variant 05 drawing dimensions 27 – Variant 05 drawing dim ensions 28 1 – Variant 05 drawing dimensions 29 – Climatic categories – Selected values 40 – minimum creepage and clearance distances 40 – I nsertion loss 42 – Return loss 43 – N EXT loss 43 – Power sum NEXT loss 44 – FEXT loss 44 – Power sum FEXT loss 45 20 – Transverse conversion loss 45 21 – Transverse conversion transfer loss 45 22 – Power sum alien (exogenous) N EXT loss 46 23 – Power sum alien (exogenous) FEXT loss 46 24 – Coupling attenuation 47 25 – Transfer im pedance 47 26 – Test group P 51 27 – Test group AP 52 28 – Test group BP 54 29 – Test group CP 55 I EC 61 076-3-1 04: 201 © I EC 201 –7– Table 30 – Test group DP 56 Table 31 – Test group EP 57 Table 32 – Test group FP 58 Table 33 – Test group GP 58 Table D – Test balun performance characteristics 64 Table F – U ncertainty band of return loss measurement at frequencies below 00 MH z 71 –8– I EC 61 076-3-1 04: 201 © I EC 201 INTERNATI ONAL ELECTROTECHNI CAL COMMISSI ON C O N N E C T O R S F O R E L E C T RI C AL AN D E L E C T RO N I C E Q U I P M E N T – P RO D U C T RE Q U I R E M E N T S – P a rt -1 : D e ta i l s p e c i fi c a ti o n fo r -w a y, s h i e l d e d fre e a n d fi x e d c o n n e c to rs fo r d a ta tra n s m i s s i o n s w i th fre q u e n c i e s u p to 0 M H z FOREWORD ) The I nternati on al Electrotechni cal Comm ission (I EC) is a worl d wid e organization for stan dardization com prisin g all n ation al el ectrotechnical comm ittees (I EC National Comm ittees) The object of I EC is to prom ote internati onal co-operation on all q uestions concerni ng stand ardi zati on in the el ectrical an d electronic fi elds To this en d and in additi on to other acti vities, I EC pu blish es I nternational Stan dards, Techn ical Specificati ons, Technical Reports, Publicl y Avail abl e Specificati ons (PAS) an d Gu ides (h ereafter referred to as “I EC Publication(s)”) Th ei r preparation is entrusted to tech nical comm ittees; any I EC N ational Comm ittee interested in the subj ect dealt with m ay partici pate in this preparatory work I nternational, governm ental an d n on governm ental organ izations l iaising with th e I EC also participate i n this preparation I EC collaborates closel y with the I ntern ational Organi zation for Stand ardization (I SO) in accordance with ditions determ ined by agreem ent between th e two organi zati ons 2) The form al decisions or ag reem ents of I EC on tech nical m atters express, as n early as possible, an i nternati onal consensus of opi nion on the rel evant subjects since each technical com m ittee has representati on from all interested I EC N ational Com m ittees 3) I EC Publications have the form of recom m endations for intern ational use an d are accepted by I EC National Com m ittees in that sense While all reasonable efforts are m ade to ensure that the tech nical content of I EC Publications is accu rate, I EC cann ot be h eld responsi ble for th e way in which th ey are used or for an y m isinterpretation by an y en d u ser 4) I n order to prom ote intern ational u niform ity, I EC National Com m ittees und ertake to apply I EC Publications transparentl y to the m axim um extent possible i n their national an d regi on al publicati ons Any d ivergence between an y I EC Publication and the correspondi ng national or regi on al publicati on sh all be clearl y in dicated in the latter 5) I EC itself d oes n ot provi de an y attestation of conform ity I n depend ent certificati on bodies provi de conform ity assessm ent services and, in som e areas, access to I EC m arks of conform ity I EC is not responsi ble for an y services carri ed out by ind ependent certification bodi es 6) All users shou ld ensure that th ey have the l atest editi on of thi s publicati on 7) No liability shall attach to I EC or its directors, em ployees, servants or ag ents inclu din g in divi dual experts an d m em bers of its technical com m ittees and I EC Nati on al Com m ittees for any person al i njury, property d am age or other dam age of any nature whatsoever, wheth er di rect or indirect, or for costs (includ i ng leg al fees) and expenses arisi ng out of the publ ication, use of, or relian ce upon, this I EC Publicati on or any other I EC Publications 8) Attention is drawn to th e N orm ative references cited in th is publ ication Use of the referenced publ ications is indispensable for the correct applicati on of this publication 9) Attention is drawn to the possibility that som e of the elem ents of this I EC Publication m ay be the su bject of patent rig hts I EC shall not be held responsibl e for identifyi ng any or all such patent ri ghts I nternational Standard I EC 61 076-3-1 04 has been prepared by subcom mittee 48B: Electrical connectors, of I EC technical com mittee 48: Electrical connectors and m echanical structures for electrical and electronic equipm ent This third edition of I EC 61 076-3-1 04 cancels and replaces the second edition, published in 2006, and constitutes a technical revision This edition includes the following significant technical changes with respect to the previous edition: a) the title has been changed to incorporate transm issions with frequencies up to 000 MH z; b) the drawings of some styles have been corrected for clarification; c) Figures 23 and 24 have been updated; – 72 – I EC 61 076-3-1 04: 201 © I EC 201 Annex G (normative) Near end cross talk (NEXT) G.1 Object The object of this test procedure shall be to measure the m agnitude of the electric and magnetic coupling between driven (disturbing) and quiet (disturbed) pairs of a m ated connector pair G.2 Test method Near end crosstalk shall be evaluated by m easuring the scattering param eters, S21 , of the possible conductor pair combinations at one end of the m ated connector, while the other end of the pairs is term inated G.3 Test set-up The test set-up consists of two baluns and a network anal yser, shall be as given in Annex D A representation of the set-up, which also shows the termination principles, is shown in Figures G and G CUT NA Port 1 00 Ω NA Port 00 Ω 00 Ω 00 Ω 00 Ω 00 Ω Measurem ent cables Screen (if an y) Ground plane Plug side Socket side Passive term inati ons shal l be resistor term inati ons Figu re G.1 – N EXT measurement differential mode only terminations IEC I EC 61 076-3-1 04: 201 © I EC 201 50 – 73 – CUT Ω NA Port 50 Ω NA Port 50 50 50 Ω 50 Ω 50 Ω 50 Ω 50 Ω 50 Ω 50 Ω 50 Ω Ω Ω 50 50 Ω Ω 25 Ω 25 Ω 25 Ω 25 Ω Measurem ent cables Screen (if an y) Ground plane Plug side Socket side IEC Passive term inati ons m ay be ei ther balu n or resistor term inati ons Figure G.2 – N EXT measurement differential and common mode terminations G.4 G.4.1 Procedure Calibration A through calibration shall be applied as a m inim um Full two port calibrations are recom mended in order to enhance the measurement accuracy G.4.2 Establishment of noise floor The noise floor of the set up shall be measured The level of the noise floor is determ ined by white noise, which m ay be reduced by increasing the test power and by reducing the bandwidth of the network anal yser, and by residual crosstalk between the test baluns The noise floor shall be m easured by term inating the baluns with resistors and perform a S21 measurem ent The noise floor shall be 20 dB lower than an y specified limit for the crosstalk I f the m easured value is closer to the noise floor than dB, this shall be reported I f the test results have high crosstalk values, it m ay be necessary to screen the term inating resistors G.4.3 M easurement The disturbing pair of the connector under test (CUT) shall be connected to the signal source and the disturbed pair to the receiver port Termination shall be m ade according to Figure G and Figure G All possible pair combinations shall be tested and the results recorded – 74 – I EC 61 076-3-1 04: 201 © I EC 201 It is recomm ended that the socket be terminated with short separated pairs without a cable jacket The CUT shall be tested in the following configurations: a) With differential and comm on m ode term inations onl y For category connectors this test is not required This requirem ent is under consideration for all categories should experience show that a test for balance can replace this requirem ent b) The m easurements shall be performed at both ends of the m ated connector NOTE As a connector is a low l oss device, near end cross talk val ues from the two en ds are n earl y equ al G Test report The measured results shall be reported in graphical or table format with the specification limits shown on the graphs or in the table at the sam e frequencies as specified in the relevant detail specification Results for all pairs shall be reported I t shall be explicitl y noted if the measured results exceed the test limits G Accuracy The accuracy shall be better than ± dB at measurem ents up to 60 dB and ± dB at measurem ents up to 85 dB I EC 61 076-3-1 04: 201 © I EC 201 – 75 – Annex H (normative) Far end cross talk (FEXT) H.1 Object The object of this test procedure shall be to measure the m agnitude of the electric and magnetic coupling between driven (disturbing) and quiet (disturbed) pairs of a m ated connector pair H.2 Test method Far end crosstalk shall be evaluated by m easuring the scattering parameters, S21 , of the possible conductor pair com binations at one end of the m ated connector, to the other end H.3 Test set-up The test set-up consisting of two baluns and a network anal yser shall be as given in Annex D A diagram of the set-up, which also shows the term ination principles, is shown in Figures H and H CUT NA Port 1 00 Ω NA Port 00 Ω 00 Ω 00 Ω 00 Ω 00 Ω Measurem ent cables Screen (if an y) Plug side Ground plane Socket side Passive term inati ons shal l be resistor term inati ons Figu re H.1 – FEXT measurement differential mode only terminations IEC – 76 – I EC 61 076-3-1 04: 201 © I EC 201 CUT 50 50 NA Port 50 50 25 Ω 50 50 NA Port 50 50 50 50 50 50 50 50 25 Ω 25 Ω Measurement cables Screen (if any) Ground plane Plug side Socket side IEC Passive term inati ons m ay be ei ther balu n or resistor term inati ons Figure H.2 – FEXT measurement differential and common mode terminations H.4 H.4.1 Procedure Calibration Calibration shall be carried out as given in G 4.1 H.4.2 Establishment of noise floor The noise floor of the setup is established as shown in G H.5 Measurement The disturbing pair of the CUT shall be connected to the signal source and the disturbed pair to the receiver port Terminations shall be made in accordance with Figure H and Figure H All possible pair com binations shall be tested and the results recorded I t is recom m ended that the socket be terminated with short separated pairs without jacket Test all possible pair combinations and record test results The CUT shall be tested in the following configurations: a) With differential terminations onl y _ There are d ifferent com bin ations for far en d crosstalk in a fou r pair conn ector, which gives a total of m easurem ents for each term ination m ethod I EC 61 076-3-1 04: 201 © I EC 201 – 77 – NOTE For categ ory this test is not requi red This req uirem ent is under consid eration for all categories should experience show that a test for bal ance can replace thi s requi rem ent b) With differential and comm on m ode term inations H.6 Test report The measured results shall be reported in graphical or table form at with the specification limits shown on the graphs or in the table at the sam e frequencies as specified in the relevant detail specification Results for all pairs shall be reported I t shall be explicitl y noted if the measured results exceed the test limits H.7 Accuracy The accuracy shall be better than ± dB at measurem ents up to 60 dB and ± dB at measurements up to 85 dB – 78 – I EC 61 076-3-1 04: 201 © I EC 201 An n e x I (normative) T n s ve rs e C o n ve rs i o n L o s s ( TCL ) and T n s ve rs e C o n ve rs i o n T n s fe r L o s s ( I.1 TCTL ) O bj ect The object of this test shall be to measure the mode conversion (differential to comm on m ode) of a signal in the conductor pairs of the CUT This is also called unbalance attenuation or transverse conversion loss, TCL I.2 Te s t m e th o d Balance shall be evaluated by measuring the com mon m ode part of a differential mode signal, which is launched in one of the conductor pairs of the CUT I.3 T e s t s e t -u p The test set-up shall com prise a network anal yser and a balun with a differential and common mode test port A representation of the set-up, which also shows the termination principles, is shown in Figure I for TCL m easurements and in Figure I for TCTL measurements CUT NA Port 50 NA Port 50 50 50 50 50 50 50 50 50 50 50 50 50 25 Ω 25 Ω 25 Ω 25 Ω Measurement cables Screen (if any) Ground plane Socket side Plug side Passive term inati ons m ay be ei ther balu n or resistor term inati ons F i g u re I – TCL m e a s u re m e n t IEC I EC 61 076-3-1 04: 201 © I EC 201 – 79 – CUT 50 50 NA Port 50 50 50 50 50 50 50 50 50 50 50 50 NA Port 25 Ω 25 Ω 25 Ω Measurement cables Screen (if any) Ground plane Socket side Plug side IEC Passive term inati ons m ay be ei ther balu n or resistor term inati ons F i g u re I – I.4 I TCTL m e a s u re m e n t P ro c e d u re C a l i b t i o n Calibration shall be performed in three steps: a) The attenuation of the coaxial test leads to the network anal yser is calibrated out by perform ing a through calibration with these test leads connected together b) The attenuation of differential signals of the test balun, a bal, DM is measured by connecting two identical baluns back to back The insertion loss of these baluns is m easured, and half of this loss is the insertion loss of the balun for a differential signal c) The attenuation of com mon m ode signals of the test balun, a bal, CM is m easured by measuring the insertion loss from the comm on mode test port of the balun to the differential output terminals The two differential output terminals shall be short-circuited and connected to the inner conductor of the coaxial test lead to the network anal yser I N o i s e fl o o r The noise floor of the set-up shall be measured The level of the noise floor is determined by white noise, which m ay be reduced by increasing the test power and by reducing the bandwidth of the network anal yser, and by the longitudinal balance (see Table D.1 ) of the test balun The noise floor, a noise, m shall be m easured by term inating the differential output of the balun with a 00 Ω resistor and perform a S21 m easurement between the differential m ode and comm on mode test port of the balun a noise is calculated as: a noise, m = −20 log S21 – 80 – I EC 61 076-3-1 04: 201 © I EC 201 a noise = a noise,m − a bal,DM − a bal,CM The noise floor shall be 20 dB lower than an y specified limit for balance I f the m easured value is closer to the noise floor than dB, this shall be reported I M e a s u re m e n t The S21 measurement shall be carried out as follows: connect the m easured pair of the CUT to the differential output of the test balun Term inate the CUT according to Clause D The balance, TCL is calculated as: a meas = −20 log S 21 TCL or TCTL = a meas − a bal,DM − a bal, CM I.5 T e s t re p o rt The measured results shall be reported in graphical or table format with the specification limits shown on the graphs or in the table at the sam e frequencies as specified in the relevant detail specification Results for all pairs shall be reported I t shall be explicitl y noted if the measured results exceed the test lim its I.6 Ac c u c y The accuracy shall be better than ± dB at the specification lim it I EC 61 076-3-1 04: 201 © I EC 201 – 81 – Annex J (normative) Termination of balun J.1 Termination of balun with low return loss for common mode I f the available balun does not provide com mon mode termination (centre tap is either connected to ground or open), a balanced resistor attenuator shall be applied in order to provide the required return loss The attenuator shall be implemented at a small printed circuit board m ounted with SMD resistors There are two cases: one for the centre tap connected to ground and one for the centre tap open J.2 Centre tap connected to ground The attenuator used shall be as shown at Figure J The nom inal attenuation is dB and the calculated common m ode im pedance is 26 Ω R1 R1 R2 R1 R1 IEC Ω R = 70 Ω R = 26 Figure J.1 – Balanced attenuator for balun centre tap grounded J.3 Centre tap open The attenuator used shall be as shown at Figure J The nom inal attenuation is dB and the calculated comm on mode impedance is 48 Ω – 82 – R3 I EC 61 076-3-1 04: 201 © I EC 201 R3 R4 R4 R3 Ω R = 82 Ω R3 IEC R3 = NOTE Resistor val ues are n om inal The nearest standard values can be chosen Figu re J.2 – Balan ced attenu ator for balun centre tap open I EC 61 076-3-1 04: 201 © I EC 201 – 83 – Bibliography I EC 60068-2-38, Environmental testing – Part 2-38: Tests – Test Z/AD: Composite temperature/humidity cyclic test I EC 6051 2-25-9, Connectors for electronic equipment – Tests and measurements – Part 25-9: Signal integrity tests –Test 25i: Alien crosstalk IEC 60603-7, Connectors for electronic equipment – Part 7: Detail specification for 8-way, unshielded, free and fixed connectors IEC 61 96 (all parts), Coaxial communication cables IEC 621 53-4-1 2, Metallic communication cable test methods – Part 4-12: Electromagnetic compatibility (EMC) –Coupling attenuation or screening attenuation of connecting hardware – Absorbing clamp method Recommendation I TU-T G.1 7, Transmission systems and media – General characteristics of international telephone connections and international telephone circuits – Transmission aspects of unbalance about earth Recomm endation I TU-T K 20, Resistibility of telecommunication equipment installed in a telecommunication centre to overvoltages and overcurrents Recomm endation I TU-T O.9, Series O: Specifications of measuring equipment – Measuring arrangements to assess the degree of unbalance about earth _ INTERNATIONAL ELECTROTECHNICAL COMMISSI ON 3, rue de Varembé PO Box 31 CH-1 21 Geneva 20 Switzerland Tel: + 41 22 91 02 1 Fax: + 41 22 91 03 00 info@iec.ch www.iec.ch