Re: PSTN + Signal Cable
In a message dated 9/18/2003, Dan Roman writes: Assuming your talking about 60950 and the signal lines are SELV you only need basic insulation, not reinforced, between TNV-3 and SELV. Distance through insulation does not come into play, just the dielectric test and voltage rating of the wire in this case. Dan, Alex: Assuming the PSTN connection that Alex refers to is either TNV-1 or TNV-3, the requirement in the base EN 60950-1 standard for separation from SELV is basic insulation (or suitable alternative) as called out in clause 2.3.2. In this case there is no requirement for 0.4 mm distance through insulation. However, for clause 6.1.2.1 (separation from earth), there is an additional requirement for 0.4 mm distance that is imposed by Finland, Norway, and Sweden per Annex ZB. Note that an alternative to 0.4 mm solid insulation is to have two layers of insulation, each of which can withstand 1500 VRMS (or maybe 1.6 time this, the wording in Annex ZB is unclear). If the TNV wires are insulated and the SELV wires are also insulated, there will be two layers of insulation and this approach will be an option. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com
Re: Approvals Matrix
In a message dated 9/5/2003, Alex McNeil writes: I have started an Approvals matrix for Europe, North America and Australasia for typical low power ITE office products. I would be extremely grateful if those experts amongst you could comment on the validity and indeed add to it. Hi Alex: Just a technicality, but TBR 21 is no longer a regulatory requirement for analog PSTN equipment in the EU. It was formally withdrawn on April 8, 2000 when the RTTE directive was adopted. Under the RTTE directive, analog PSTN products are only subject to the applicable safety and EMC requirements. Many manufacturers have been uncomfortable with having no regulations whatsoever for the parameters formerly covered by TBR 21, so they have continued to self-impose TBR 21 compliance. However, TBR 21 has no regulatory significance. You may be interested to know that last month ETSI issued an updated document that is intended to replace TBR 21 as an advisory standard. The document number is TS 103 021, and it is available for download on the ETSI site (in three parts). In this document, some of the TBR 21 requirements have been revised and some new requirements have been added. Thus, if you want to show an advisory standard in your matrix, you should probably list TS 103 021 instead of TBR 21. The current analog PSTN spec for Australia is AS/ACIF S002:2001. For New Zealand the current spec is PTC 200 (1997). The safety requirements for all of the countries in your chart are based on IEC 60950, but each country has their own version with its own name. In Europe it is EN 60950, in the USA and Canada it is a binational standard often referred to as UL/CSA 60950 (but technically UL 60950 and CAN/CSA-C22.2 No. 60950-00), and in Australia I believe it is (finally) AS/NZS 60950. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com
Re: PCB line spacing for NEBS 1089 1st Level lightning test.
In a message dated 8/11/2003, do...@aiinet.com writes: How can I determine the best line spacing for high voltage pulses on differential pairs? Should the voltage be calculated at protection device's clamping voltage? How does the formula change for interlayer vs. top/bottom layer? Is there any good reference material? Hi Doug: If your question is what level of voltage-withstand you need to maintain between the conductors of a differential pair, you are pretty much on the right track by tying it to the maximum trigger voltage of the differential protection device. With a protection device that triggers in the range of 350 volts worst case, the spacing can be quite small, on the order of 0.3 mm. For this condition, any layer-to-layer separation will be more than adequate. For differential pairs that have such a protection device, a key issue that I have seen some people overlook is that after the fuse blows during the Level 2 power cross tests, the voltage tip-to-ring will reach 600 VRMS in the section between the network connector and the fuse. Any arcing under this condition will cause the wiring simulator to open, resulting in a failure of the test. I would suggest tip-to-ring spacing of at least 1.5 mm for this area. The issues regarding spacing get more complex when you are looking at pair-to-pair or pair-to-ground separation. In that case you will be dealing with voltages up to 2500 volts peak under the Level 1 surges in GR-1089. However, your question seems to be targeted at the separation between two conductors of a differential pair, which I have tried to address above. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com
Re: Lightning Surge Characterization/Standards
In a message dated 8/5/2003, a...@occamnetworks.com writes: We have products that meet all the Surge requirements of NEBS GR-1089, FCC-68 and EMC 4-5. But, the same products are continuously failing in the field due to real-world lightning strikes. I have spoken to four other manufacturers who make similiar interfaces (DSL) and they all have the same problem : they meet the standards, but fail in the real world. Hi Anil: I am familiar with the problem that you describe. In general, I believe that the GR-1089 requirements are fairly appropriate, although the FCC-68 and EMC 4-5 are not really adequate for good performance in the field. In my experience, if you are passing GR-1089 and are still experiencing field failures, the cause is likely to be one of the following: 1) Many test labs do not perform the GR-1089 tests properly. For example, some labs only test the equipment in an unpowered state, rather than testing all operating states. It is sometimes difficult to apply surges with the equipment held in a legitimate operating mode with all the proper conditions (DC battery, etc.). Another thing that some test labs skip is testing the sneak-under surge tolerance per Note 5 of Table 4-2 of GR-1089, Issue 3. 2) I have seen some DSL interface designs that failed only when used in combination with primary protectors. For example, certain capacitors within the DSL interface can charge up on the rising edge of the surge, but will discharge rapidly when the primary protector fires. Sometimes this discharge path damages the line driver IC. If the test is performed with no primary protector, everything works fine. The requirements in the 2000 editions of ITU K.20 and K.21 seem more directed at uncovering this type of problem than the coordination requirements in GR-1089. 3) All the standards that you reference, including GR-1089, *assume* that there is a primary protector in place that will limit differential surges to about 1000 volts peak and common mode surges to about 2500 volts peak. This is probably an acceptable assumption for central office equipment that is generally well maintained, but for customer premises equipment the primary protector is sometimes inoperative. A common problem is that the ground wire for the primary protector has been inadvertently disconnected. Regarding problem #3 above, the situation is not as dire as it first appears. Even with no primary protector installed, differential (metallic) surge voltages will tend to be limited by the secondary protection in the DSL interface. The short-circuit currents typically do not exceed 100 amps. For common mode (longitudinal) surges, the open-circuit voltage will be limited only by the internal breakdown threshold in the telco cable and infrastructure, unless the DSL interface also contains common mode protection to ground. I have only been able to locate limited field studies of what the upper bound of such surges might be, but the consensus view seems to be that it is in the range of 4000 to 6000 volts with no primary protector. If any list members are aware of published studies on this parameter, please let me know. Where possible, I prefer to implement a 5000 volt isolation barrier that has inherent resistance to common mode surges. This is generally easy to do in transformer-coupled DSL circuits, especially in customer premises equipment. In some central office equipment, protection to earth ground is required for other reasons, so the focus turns to short-circuit current rather than open-circuit voltage. To comment further on possible causes of the specific failures that you are experiencing, I would need to see a schematic of your present interface and a description of the failure mode. However, I think there is a good chance that the cause of the discrepancy (pass GR-1089, fail in the field) is related to one of the three items listed above. The good news is that it is possible to achieve low failure rates in the field without spending a lot on interface protection. The first thing you need to do is carefully compile a list of appropriate tests. I think that GR-1089 (properly performed) is a good starting point, but you may want to add supplemental tests to cover items 2 and 3 above. Once you have identified the tests that you want to pass, some careful attention to the architecture of your protection circuit will usually yield a suitable circuit at minimal increase in cost and/or board area. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com
Need help with Japanese language draft standard
Hello All: I have been given copies of two Japanese language documents that reportedly describe some proposed new telecom requirements in Japan. The first document appears to be a cover letter from the committee, while the second document appears to be the draft standard itself. I have been told that the draft standard proposes making with ITU K.21 compliance mandatory for modems, although I suspect this is not true. I can not read the Japanese text, but I do see many references to various DSL standards. I do not see any reference to K.21. As it turns out, the two documents are posted at the following URLs: http://www.soumu.go.jp/s-news/2003/030617_5.html http://www.soumu.go.jp/s-news/2003/pdf/030617_5_a.pdf I am hoping that some group members who can read Japanese could briefly check these two documents on the web and answer a few questions for me: 1) What is the subject matter of these two documents? 2) What is the Ministry of Public Management, Home Affairs, Posts and Telecommunications (on whose web site these are posted), and how does this organization relate to JATE? 3) Is this a draft regulatory standard or a draft industry standard? 4) Is there any indication that compliance with ITU K.21 may become mandatory in Japan? Any insight that the group members can provide would be most appreciated. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: IEC65 7th edition, creepage clearance
In a message dated 7/2/2003, Chris Colgan writes: A designer wants to place a ground plane above a mains track on a pcb, contained within a 230V rated domestic type product. As far as I can tell, 1) The minimum thickness of the pcb material between the ground plane and track should be 0.4mm, the insulation resistance between the two be 4Mohm and the dielectric strength test be 3kV(rms). (Clause 8.8) Hi Chris: I'm not familiar with the details of IEC 65, but in IEC 60950-1, clause 2.10.5.3, titled Printed Circuit Boards, describes several circuit board construction methods that can be used as an alternative to the 0.4 mm thickness requirement. These generally relate to using two or more layers of thin sheet insulation, which is pretty easy to do in a circuit board. I suspect that you may find similar options described somewhere in IEC 65. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com
CE marking for professional audio equip
Hello All: Sorry to ask what will be an obvious question to some of you, but what standards apply for CE marking of professional audio equipment? I'm a telecom guy, but I have been asked about professional audio equipment and do not know the answers. The product in question is a digital reverb processor that is typically used in a professional recording studio. For those who have been following the recent LVD discussion on the list, I should note that this product is basically a SELV device that uses a CE marked wall wart power supply. The wall supply is connected to the SELV unit with a hardwired cable. I am interested to know what safety standard applies to this product, and whether additional testing is required beyond the existing power supply approval. I am also interested in what EMC requirements apply, and whether the emissions classification would class A or class B. Any insight would me appreciated. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Separation between charging circuits and TNV-3(UL60950)
In a message dated 5/2/2003, you write: For cordless phone, in most cases, the charging circuits are touchable. So based on 6.2.2.2, we need apply 1000Vac between the charging circuits and TNV-3. Usually it'll fail if there is no isolation transformer after Tip and Ring. Most of the manufacturers don't want to add an isolation transformer to avoid increasing the cost. So does anybody there have any idea to solve this problem without an additional transformer? Hi Carl: There are several ways to solve this problem, but the most straightforward options are the ones that you have already identified: 1) Make the charging contacts inaccessible. Note that you can probably call these contacts connectors and use the blunt probe. Another approach would be a mechanical interlock that only connects the charger when the handset is in the cradle. 2) Use a transformer in the phone line interface. Suitable transformers only cost 30 to 50 cents in high volume. The total cost impact might be more or perhaps less, depending on how the related circuits are affected. It is worth noting that transformer interfaces simplify some other design considerations, such as RF immunity and lightning surge tolerance. In some designs I have done, the transformer was optional because it was not needed for isolation, but I ended up using it anyway because the total cost impact was small and there were performance advantages. 3) Isolate the charger, using either transformer or capacitor isolation. Since the caps would have to stand off 1000 VRMS, a transformer might be the best choice here. Also, don't overlook the requirement for basic insulation in clause 2.3.2 (UL 60950-1). If this product will be sold in Europe, watch out for the additional requirements in Annex ZB of EN 60950-1. There are some other compliance schemes you could use, but they get complicated. It is probably best to stick with one of the simple approaches listed above. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com
Re: Lightning coordination in K.20 (2000) versus GR-1089
In a message dated 4/21/2003 Marko writes: I don't have much technical to add but was wondering why you are looking into this standard. Have you customers that are asking for this requirement to be met or is it simply a planning exercise? If it's customer-driven, could you share what type of customer (ILEC, PTT, North America, European, Asian, etc.)? Hi Marko: This issue was first brought to my attention by a client that makes DSL equipment for a PTT customer in Asia. However, it is likely to eventually become a problem for compliance in Europe and South America, where the regulatory requirements typically refer to K.20. I think there may be a transition period, because many of the applicable regulations refer specifically to earlier editions of K.20. However, whenever a regulation that references K.20 is updated, it typically calls out the latest edition. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com
Re: Lightning coordination in K.20 (2000) versus GR-1089
In a message dated 4/17/2003, you write: As an FYI, we see very few instances of damage on our carrier class products due to lightning events. As such I doubt the coordination issue is really that significant. Hi Jim: Thanks for your detailed discussion of the coordination problem. I share the concerns you expressed, particularly your general discomfort with the surge tolerance of PTC devices. I should also mention that my own experience is that GR-1089 compliant products rarely have lightning failures in the field. I have seen some cases where the *voltage* of real world longitudinal lightning surges exceeded what GR-1089 tests for, due to nonfunctional primary protectors. GR-1089 makes no attempt to treat this field condition as a Level 1 test, but experience has taught me that it must be considered. On the other hand, I have not seen any significant incidence of cases where the short circuit *current* was enough to damage a GR-1089 compliant design. Fuses that can handle a 10x1000 uS, 100 amp surge almost never fail in the field. This suggests to me that the coordination requirement in the new K.20 is excessive, and that the coordination requirement in GR-1089 is probably more closely aligned with actual field conditions. GR-1089 does not require the primary protector to operate if the secondary protector can handle 10x1000 uS 100 amp surges. I wonder whether there is any room for the authors of K.20 to consider lowering the amount of short circuit current that the secondary protection must be able to survive in order to waive the requirement that the primary protector must operate. The present K.20 level of 1000 amps is extraordinary. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com
Lightning coordination in K.20 (2000) versus GR-1089
Hello All: I have been studying the new 2000 edition of K.20, Resistibility of Telecommunication Equipment Installed in a Telecommunication Centre to Overvoltages and Overcurrents. There appears to be an important change from the previous edition that will have a big impact on line interface design. I would like to get some feedback on whether I am understanding this properly. The change that concerns me is that for test 2.1.2 (4000 volt surge on twisted pair phone lines), K.20 now requires that the primary protector *must* operate. If there is any kind of secondary overvoltage protection internal to the equipment under test (EUT), requirement 2.1.2 pretty much forces the EUT to contain series resistors in front of the internal protection. Otherwise, the internal protection will prevent the external primary protector from operating. The requirement for the primary protector to operate can be waived if the protection internal to the EUT itself meets the requirements for a primary protector. However, this includes passing the test of 2.1.5 with vaguely specified surges of 1000 amps per wire and (presumably) open circuit voltages of 4000 volts. I note that in Telcordia GR-1089, the requirement to coordinate with the primary protector can be waived if the EUT can survive a 10x1000 uS, 100 amp surge (clause 4.6.7.1 of the 2002 edition). This requirement is fairly easy to meet without using series resistors. I find it interesting that series resistors have never been required for compliance with GR-1089, which itself is a pretty rigorous standard, nor were they required for previous editions of K.20. Now, it appears that manufacturers must decide at the outset whether their GR-1089 compliant products might ever go into a market where K.20 compliance is required. If so, the resistors have to go in the design. The series resistors needed to pass the new K.20 requirement are not ordinary resistors. Typically, they are large, wirewound, surge tolerant, flameproof resistors with steady state ratings of several watts. Two of these per port on a high density, multiport board is a big hit on board area. Furthermore, the added resistance is very detrimental to some types of DSL transmission. In other words, this change in K.20 looks like it will have a big impact on line interface design. My questions are as follows: 1) Is my understanding of the new coordination requirement in K.20 correct? 2) Is there a simpler way to comply with the requirement other than using series resistors? 3) Has there been any industry feedback to the ITU complaining about the coordination requirement as presently written? 4) Is there evidence that the 10x1000 uS, 100 amp waiver in GR-1089 is inadequate, justifying the much more stringent waiver requirement in K.20? Any and all comments on the above would be most welcome. I'm just trying to make sense out of the new requirements. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Use of the # button on telephone dial
Hello All: Sorry if this is a little off-topic, but is anyone aware of any central office features, or other network features, that use the # button on the standard telephone DTMF keypad? I know of some features that use the * button, but I am unaware of any that use #. I have been asked about assigning this button to a special feature, but I want to make sure that there are not other conflicting uses in some countries, or any prohibitions on its use. Thanks, Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Capacitors bridging basic and supplementary insulation
In a message dated 3/14/2003, you write: As I understand it, for 60950, basic insulation is required between TNV-3 circuits and chassis ground, and supplementary insulation for Sweden and Norway. Do capacitors bridging basic and supplementary insulation (i.e. tip and ring to frame ground) have to comply with IEC 60384-14? Hi David: In Annex ZB of EN 60950, Third Edition, Norway and Sweden explicitly call out Y2 caps per EN 132400:1994, which I believe is based on IEC 384-14. Under EN 60950, Second Edition, the situation is less clear and there are some different interpretations in use. I believe that Semko has issued an interpretation that under the Second Edition, Y3 caps can be used if they are subjected to an additional surge test. Some other labs, however, will accept any cap as long as it meets the applicable requirements for creepage, clearance, and hipot. I think the Second Edition will be withdrawn in 2006, so there are a few years still where Y3 caps can be used. Novacap (http://www.novacap.com) sells surface mount versions of both Y2 and Y3 caps. In general, the through-hole ceramic disc versions are much less expensive, since they are manufactured by a large number of companies including some Asian suppliers. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com
Amendment 1 to CISP24:1997 adopted in EU?
Hello All: The conducted immunity limits for voice equipment in Tables A.1, A.2, A.3, and A.4 of EN 55024:1998 are very difficult to meet. I have a copy of the IEC Amendment 1 to CISPR 24, dated July 2001, that significantly relaxes these limits. Was this amendment ever adopted by the EU to become part of EN 55024? If not, is there any likelihood that it will be adopted soon? Thanks, Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Hazardous to SELV separation on internal PCB layers
In a message dated 2/25/2003, Chris Maxwell writes: What if I were to specify a circuitboard with .006 layer to layer spacing between an SELV layer and a hazardous layer? Obviously, this is less than .016. Furthermore, the drawing would specify to the PCB maker that they must use at least three layers of laminate to make this spacing, for instance, three sheets of .002 fiberglass? Can anybody shoot holes in this design from an EN 61010-1 perspective? BONUS QUESTION: WHAT ABOUT HAZARDOUS/SELV SEPARATION BETWEEN TRACES ON THE SAME, ***INTERNAL*** LAYER? Hi Chris: I work mostly with EN 60950, so I'm not sure how clear EN 61010-1 is on this topic. However, clause 2.10.5.3 in EN 60950 provides a very clear description of what is acceptable for both layer-to-layer and trace-to-trace on the same layer. You might want to read this just to get an idea of what the authors of EN 60950 were thinking. In general, the approach you describe of specifying three layers of .002 inch material would meet the layer-to-layer requirement in EN 60950, but you would always be vulnerable to a screw-up at the board fab house. If your board is a multi-later board, there are a couple other options that help reduce the risk: 1) Put SELV on the top layer and HAZ on the bottom, with no copper on inner layers in that area. This gives you the full board thickness for insulation. 2) If there are several layers in the board, keep one or two layers between the SELV and HAZ void of copper. This provides a simple guarantee that you will always have the desired 2 or 3 layers of thin insulation between SELV and HAZ, regardless of how the board fab house constructs the board. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com
Re: rj45 with integrated magnetics..
In a message dated 2/3/2003, Muhammad writes: Also, I would appreciate if someone could point me to a document where I could find rules/factors to consider while selecting a jack with integrated magnetics. Hi Muhammad: One thing to watch out for with integrated magnetics is that some of these designs do not do well with safety isolation and/or the lightning and power cross requirements in Telcordia GR-1089 and EN 300 386-2. For some applications these standards are important, while for others they are not. Just make sure you know what your regulatory requirements are before you commit to an RJ-45 with integrated magnetics. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com
Is pulse dialing still needed in Australia?
Hello All: I am trying to cost reduce an older, worldwide PSTN line interface design. This circuit contains a pulse dialing transient limiter that was needed to meet the pulse dialing requirements in the Netherlands and Australia. I would like to take this circuit out and restrict dialing to DTMF only in the Netherlands and Australia. I know that in the Netherlands, 100% of the PSTN lines now accept DTMF dialing, but I don't know if the same is true for Australia. A few years ago I was told that Australia would be 100% DTMF compatible soon, but I do not have reliable confirmation that this transition has been completed. Can any of you confirm that Australia's PSTN is now 100% DTMF compatible? Is there an official source that I can reference for this information? Also, can you confirm that there is no additional charge to use DTMF in Australia? I know this may sound ridiculous to those of you outside the USA, but when DTMF dialing was first introduced in the USA, the operating companies typically charged extra for the service. In some states, those charges are still being applied. Thanks, Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 j...@randolph-telecom.com http://www.randolph-telecom.com This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Switzerland Compliance Homologation Requirements
In a message dated 1/10/2003, Jeffrey Collins writes: Does anyone have any current information on telecom requirements in Switzerland? Hi Jeffrey: Last time I looked into this (about a year ago), Switzerland had incorporated the provisions of the RTTE directive into their national law. As you know, they are not legally obligated to follow the RTTE directive because they are not a member of the EU, but as a practical matter the requirements are the same. Even before the RTTE directive, the Swiss requirements were pretty straightforward. For analog PSTN requirements they took TBR 21 and made a few minor revisions. You will have to watch out for 12 KHz meter pulses, though, because these are still widespread on the Swiss network. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 http://www.randolph-telecom.com
