Hello All:
Just a quick followup on our discussion about the short circuit tests:
I just received my copy of Issue 3 of GR-1089, and when I went to replace
Issue 2 I found a 1-page bulletin from Telcordia, dated December 1999, tucked
in the front of my Issue 2 binder. The bulletin
In a message dated 11/27/2002, Marko writes:
So what did you decide? Is a fuse blowing acceptable?
I'm sure others would be interested as well.
Hi Marko:
So you want me to go on the record so I can get flamed? OK, here goes:
The revised text in Issue 3 of GR-1089 (kindly posted to the
Hello All:
Many thanks to all who responded to my question about this requirement. Many
of the responses were quite interesting and persuasive, even though some of
them were directly opposed. I think that the expanded description in the new
third edition of GR-1089 helps resolve most of the
In a message dated 10/21/2002, Paul Denomme writes:
I am currently working on a design for the telecom industry. I need to
determine the minimum specifications for setting up my design rules for
both internal and external layers and connector selection. According to
UL60950 table 2N the
In a message dated 10/8/2002, Alex McNeil writes:
As I am in panic mode, is there some guidance out there for me e.g. is it
usually a matter of changing the interface IC's or hanging special
components onto the lines?
Hi Alex:
This test is indeed a difficult one to pass, but in general
In a message dated 9/19/2002, Ken Javor writes:
I am getting multiple postings, even I think into the next day.
Me too. I have even seen my own postings come back around with the CC
field populated with multiple copies of the listserver address, even though
that is not how the CC field
In a message dated 9/19/2002, Matt Aschenberg writes:
Our engineering team is looking for a spec that defines U.S pulse dialing.
Any suggestions?
Hi Matt:
As you may know, there are no regulatory requirements for pulse dialing in
FCC part 68. This means that any requirements you apply
In a message dated 9/19/2002, you write:
So far, I've taken a large resistive load and measured the voltage drop on
the AC line. From that I calculated the total impedance of the AC line.
However, as you may suspect, with a resistive load, the power factor is
1.0.
So I can't vectorly,
In a message dated 9/19/2002, you write:
So far, I've taken a large resistive load and measured the voltage drop on
the AC line. From that I calculated the total impedance of the AC line.
However, as you may suspect, with a resistive load, the power factor is
1.0.
So I can't vectorly,
In a message dated 9/17/2002, Rob Keller writes:
So, because of the ring signals, which would exceed the
limits of SELV, connecting to the input the modem, should the
classification be TNV-3.
Hi Rob:
If the tip/ring pair that the DSL modem interfaces to has power ringing on it
(such as
In a message dated 9/12/2002, Scott Douglas writes:
We use gas tubes in our products for protection against lightning and/or
surge. We now have an edict to get them out of all of our products. So what
does one use to provide similar protection without using a gas tube?
Hi Scott:
Well,
Marko Radojicic writes:
Battery Return is also problematic. In NA, it *must* be held isolated from
CG/FG. In the EU, it *must* be bonded to the CG/FG!
Hi Marko:
Thank you for your very informative response. I would just like to clarify
any possible distinction between battery return and
In a message dated 9/10/2002John Juhasz writes:
Be careful Dorin. For Central Offices, they need to be isolated.
Hi Guys:
I changed the subject heading on this response (was Inrush and EN61000-3-3)
to better reflect the direction this thread has taken.
The subject of isolating circuit
In a message dated 8/30/2002, mra...@attbi.com writes:
What you got is exactly as stated in their specification.
http://www.tripplite.com/products/product.cfm?productID=228
This helps a lot. I had performed a web search earlier for specs on the
IS-1000, but I did not turn this up.
In a message dated 8/30/2002, Don Borowski writes:
But there is common mode supression (hot and neutral against safety ground)
offered by the transformer, assuming that the capacitive coupling between
the
primary and secondary is minimal.
...There is one effect of a long run of bundled
In a message dated 8/30/2002, Chris Maxwell writes:
Most isolation transformers have a non-magnetic, metal shield between the
primary and secondary. The shield does not appreciably degrade the
transformer's magnetic coupling at 60Hz; however, it does attenuate the
high frequency
In a message dated 8/28/2002, Chris Maxwell writes:
Can anyone see any pinholes in my reasoning? Can anyone recall the thread
regarding multiple layers of thin insulation?
Hi Chris:
Wow, you are really pushing the limits with your board design. I work with
EN 60950, and the clause in
In a message dated 8/15/2002, Gary McInturff writes:
Okay, now don't everyone write to my layout guys, but I never bothered to
tell them they could change the constraint files for closer routing on
inner layers, so they do apply the spacings. I have try to keep an eye for
it causing us
In a message dated 8/13/2002, you write:
To me, it's sort of funny in that it just says that the Creepage and
Clearance distances do not apply on inner layers of void free PCBs.
That's nice; but I can't find where a distance is specified. I mean, I
would think that there should be some
Hi Muhammad:
The discussion on this thread has prompted me to think further about why I
have not used integrated magnetics for NEBS applications in the past. My
earlier response was based on what I could recall at the moment, and was only
partially accurate.
If you use a device that has a
In a message dated 7/22/2002, Muhammad writes:
For boards with copper ports (100baseT and 100base T), is it possible to use
rj45 connectors with integrated magnetics and still get pass these tests.
Hi Muhammad:
Previous respondents have clarified that typically you will be subject to the
In a message dated 7/8/02 10:36:19 AM Eastern Daylight Time, Alex McNeil
writes:
Q1. Is 2.5mm OK (Norway and Sweden are to be included) and what is the
minimum?
Q2. Does this creepage and clearance need to apply to all 6 layers (and 4
layers)?
Hi Alex:
I am out of my office for the
In a message dated 7/8/02, Dieter Baldamus writes:
I have a telecom unit that already passed all tests according to CS03, FCC
part 68 and NRT3. What are the chances to pass the Australian TS001 and
TS002 without modifying the unit?
Hi Dieter:
The following items are the key ones you
In a message dated 6/19/2002, Dave Hutchins writes:
Energy has nothing to do with the capability of the TVS device. It is also
proven that the energy in the transient threat is not the energy dissipated
in the TVS component, just ask any old timer even those at Harris.
Hi Dave:
I'm not
In a message dated 6/19/2002, Bob Wilson writes:
Transzorbs (or TVSs) are basically zener diodes that are rated for
their energy absorption capability.
Hello All:
One thing to keep in mind is that the energy handling capability of a
TransZorb is generally not very high compared to other
In a message dated 6/19/2002, Alex McNeil writes:
For the PSTN analogue modems I am not so sure:
FCC Part 68 vs CTR21 (TBR21)?
Can anyone offer some advice here?
I assume if the product meets CTR21 then the modem should function OK in
Italy?
Does Italy have other modem details that I
Hello All:
I am trying to determine whether there are any published requirements for
lightning immunity or power cross for wireline PSTN terminal equipment in
Japan. The JATE requirements for PSTN terminal equipment do not contain any
such tests, and I am not aware of any similar
In a message dated 5/8/2002, John Juhasz writes:
it appears that it is not required to test the interface itself to
'telecom specs' such as those in the CTR21.
Hi John:
Your interpretation is correct. For wireline POTS products/interfaces, the
only requirements that apply under the
In a message dated 4/19/2002, you write:
My summarized Analogue Modem Requirements
TBR21 + EG 201 121 (Europe)
FCC Pt 68 (Mexico and Canada acceptance?)
TS002 (Australasia, no PTC 200?)
Hi Alex:
As Ron Pickard has already pointed out, Mexico's telecom requirements are not
fully
In a message dated 3/7/2002, John Woodgate writes:
If such a modem meets the 60 mA requirement, is there really a problem?
Hi John:
A modem that does not provide 60 mA limiting will be suitable for use in a
wider range of countries, and will be less expensive to implement. The need
for
Hello All:
Recent discussions on the emc-pstc listserver indicate that the Czech
Republic has made an effort to harmonize their regulatory scheme with the
European Union's RTTE directive. I have reviewed the text of the Czech
legislation, Act 151/2000, and find that it has some similarities
In a message dated 2/4/2002, Chris Maxwell writes:
What would happen (assuming 60950) if you had AC on the component side
of a board and SELV on the solder side. (assuming that any through holes
were properly cleared out).
Hi Chris:
That usually works out fine, since the board is
In a message dated 2/1/2002, John Juhasz writes:
In short, they noted that while possible, it is difficult to maintain the
pollution degree 1 in a printed circuit. Typically the pollution degree
is applied to 'potted' items.
Hi John:
In the first edition of EN 60950 there was little
In a message dated 1/31/2002, Rick Busche writes:
Does the application of a solder mask allow for a change from pollution
degree 2 to pollution degree 1? I understand that conformal coating
requires significant testing when used to reduce spacings per table 7, but
in this case I am only
Hi Bob:
The 120 ohm resistor you mention is typically placed across the line on the
transceiver chip side of the isolation transformer. While you might be able
to get away with putting it on the line side, I do not see how this would
provide any protection. There is a big difference between
In a message dated 1/15/2002, A
HREF=mailto:jfinlay...@telica.com;jfinlay...@telica.com/A writes:
You'll need to comply with the Intrabuilding Lightning requirements
of GR-1089. I'm not sure about the 12 mil question.
Hi Bob:
Joe is correct about the intrabuilding surges in GR-1089. I
In a message dated 11/27/2001, Jerry Martin writes:
I'm working on a product that is telecom network powered (-190 Vdc) and will
most likely require a production line hipot test. Being network powered, it
is exposed to outside plant surges and has transient protection designed in
(fuse
In a message dated 10/25/01, Dave Heald writes:
If you want to ship to Europe, the nominal voltage can be -60Vdc. Here
it gets tricky as charging voltages are typically 72Vdc. Most NRTL's
testing to the new UL60950 will treat DC input voltages at these levels
as TNV-2, which is a lot
In a message dated 10/23/01, Gregg Kervill writes:
Have lines ever been struck by Lightning?
One of my clients had a cupboard full of telephone products destroyed by
all sorts of bazaar events - like the temporary three phase power line to a
factory that fell' across domestic phone
In a message dated 10/23/01, Perry Hopkins writes:
My question is; by definition, shouldn't the DSL circuits fall under the
TNV-3 and not Hazardous Voltage secondary circuit. The major difference is
when you are determining the creepage and clearance distances. At TNV-3
you are allowed
In a message dated 8/29/01, Andy White writes:
When does an Ethernet interface require JATE approval? Is the approval only
reqd. when connected to a Leased Line? or does it apply when connected to a
local building ethernet network?
Hi Andy:
Ethernet is not a service offering on the
In a message dated 8/24/01, Ken Hall writes:
What equipment is generally used to test the acoustic noise levels specified
in CISPR 24 Annex A while performing Radiated and conducted immunity?
Hi Ken:
There are special microphones and measuring equipment that can be used for
acoustic
In a message dated 8/20/01, David Gelfand writes:
Having had much difficulty meeting these limits, could you briefly
summarize
the changes in Am1? Do they apply also to PSTN lines also?
Hi David:
I'm out of the office this week, so I don't have the amendment handy.
However, as I recall
In a message dated 7/23/01, Ghery Pettitwrites:
You can purchase a copy of Amendment 1 to CISPR 24 from the IEC web page
(http://www.iec.ch) for all the details. The amendment primarily deals with
analog telephone sets.
Hi Ghery:
Thanks for the info on this. I downloaded the amendment
In a message dated 6/29/01, David Gelfand writes:
What other countries besides CE have immunity requirements similar to EN
55024
or EN 50082?
Korea is one example. I think Singapore is phasing in some immunity
requirements.
Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
In a message dated 6/28/01, Geoff Lister writes:
EN55022:1998 section 9.5 indicates that measurements must
be made on telecommunication ports, and covers, in great detail
Hi Muriel:
Geoff has provided a succinct answer to the question you posed. I just want
to add that you will also have
In a message dated 6/22/01, Chris Maxwell writes:
I have a test sample that has one of these serial ports on it, and I can't
find a cable assembly to mate with it. I have called my usual cable
assembly vendors with no luck. I now throw myself at the collective wisdom
and mercy of the group.
In a message dated 5/29/01, Dan Roman writes:
I am looking for a relay that can be used without restriction for a fail
over function between CO trunks and station sets in a PBX type application.
The fail over relays switch select CO trunks over to individual phones
should the PBX fail or
In a message dated 5/24/01, David Gelfand writes:
When we inject as per IEC 61000-4-6, the 1 kHz tone is demodulated and is
VERY loud in the telephone earpiece! This happens no matter which i/o
cable we inject, even the power cord.
Hi David:
While it is not surprising for an
In a message dated 4/24/01, Kevin Harris writes:
We just ran across a nifty piece of standards writing. In Australia in of
their telecom standards (TS002) there is the following safety statement in
it.
5.1.1.2 CE should not cause harm or damage to a Telecommunications Network
or Facility
In addition to the various mechanisms for intra-building lightning that have
been postulated on this thread, there is one other that I have heard
reference to.
If lightning strikes the top of a building, the path to ground is often
through the steel frame of the building. When this happens,
Dear All:
It is my understanding that South Korea has adopted a set of EMC immunity
requirements that are similar, but not identical, to the ones that the EU
imposes. I believe that the scope of the requirements includes ESD, radiated
RF immunity, EFT, surge, and voltage drops.
So far, I
Dear Listmembers:
I would like to purchase a CDN (coupling-decoupling network) for performing
the conducted RF immunity test called out in EN 55024. The specific CDN that
I am interested in is the CDN-T2 for 2-wire unshielded twisted pair, as
shown in Figure D.4 of 61000-4-6.
Can any of you
In a message dated 1/17/01, Courtland Thomas write:
I have a question concerning coninuing compliance for Part 68. I believe
that we are required to submit units for testing every six months. If the
FCC audits and finds that the test reports aren't up to date, then there can
be problems. This
In a message dated 1/15/01, John Juhasz writes:
I am trying to find a second-source for a TVS (Transient Voltage Suppressor)
that I now use to meet the 61000-4-5 1.2/50us 1kV transient.
Hi John:
To finalize the requirements on the surge suppressor you need, you will have
to determine
In a message dated 1/2/01, Gaétan Hogue writes:
I have an TNV-1 interface (ISDN) on a card going in a computer.
Some of my designers told me that we need reinforced isolation
transformer(3kv) in Norway.
Hi Gaétan:
The main requirement for reinforced insulation is between the TNV-1
In a message dated 12/27/00, Zohar Zosmanovich writes:
I'm concern about designing a proper protection from Surges, applies on
ports for indoor signal lines (E1, Ethernet) at telecommunication centers.
According to ETSI EN 300 386 a surge of 1.2/50 us, 0.5 kV shell be applied
between Tip
In a message dated 12/21/00, you write:
He also said that meeting the 500 V ac or 707 V dc requirement was not
Hi David:
Thanks for the feedback. Can you elaborate on the reference above to the
500 VAC or 707 CDC requirement? What clause does this requirement derive
from? Was your CSA
In a message dated 12/12/00, Peter Merguerian writes:
Assume you have equipment with external power earthed (Class 1) power
supply with an earthed appliance inlet for conenction to the mains. The
power supply output is connected to a dc unit with a TNV-2 interface with
no separation to SELV.
In a message dated 12/11/00, Dave Lorusso writes:
If a telecom product is permanently connected (-48 Vdc Central Office
Equipment), is it exempt from paragraph 6.3.3 Separation of the
telecommunication network from earth, of UL 1950? I'm reading this as there
is no physical spacing required
In a message dated 9/26/00, John Juhasz writes:
Personally I see this as a Medical Device with 'Telecommunications
Feature'.
Therefore, I envision the application of the applicable Medical Device
standard with a separate test (report addendum) on the telecom port
utilizing an
In a message dated 8/31/00, Matt Aschenberg writes:
The fast transient has a ringing (underdamped) wave form. Our primary
concern is to protect the modem against lightening surges. We currently
test
to 6kV underdamped and overdamped.
Hi Matt:
If your primary concern is lightning
In a message dated 7/28/00, Allan Carr writes:
COMMISSION DECISION of 26 May 2000
concerning the request by France to maintain pursuant to Article 18(3)of
Directive 1999/5/EC of the European Parliament and of the Council (the
RTTE Directive) a requirement for telecommunications terminal
Hi Peter:
Back on July 11, you posted a question asking about the safety and EMC
requirements for dialers. I meant to respond, but got busy and forgot. Did
you get the info you needed?
I am not sure what you mean by dialer, but in my mind this usually refers
to a device that is placed in
In a message dated 5/23/00, David Gelfand writes:
We have an emissions problem on a board and I would like to suggest a
ground
plane in the area of an RJ-45 jack (TNV-1). But we have always asked our
PCB
designers to leave TNV traces free of ground and power planes to avoid
arcing
In a message dated 3/10/00, Steve Phillips writes:
EMC gets a lot more traffic (if appears
to me anyway) - and I am more concerned with
safety, which leaves me filtering and deleting a
lot more messages than I would like to have to -
it wouldn't be so bad if EMC and Safety messages
In a message dated 3/9/00, Scott Lacey writes:
I am looking for a source for leadless disc capacitors. I require 10,000 pF
of at least 3kV. Basically, what I'm looking for is to buy capacitors that
have not yet had the lead attachment and coating operations performed. I am
trying to
In a message dated 1/21/00, John Boucher writes:
What I'm really wrestling with is whether we need to be concerned about
power
line cross / induction issues outside of North America.
John:
I too have heard the argument that AC mains wiring outside of North America
is different, and
Listmembers:
I have a question that perhaps some of you can help me with. I'm developing
a regulatory compliance plan for a new telecom product that is scheduled to
begin shipping in the first quarter of 2000. The exact date is not certain,
but it is likely to be before the April 8, 2000
Hello All:
I am hoping that some of you can help me gain an understanding of the
requirements for intrinsic safety for communication wiring that is used in
a manufacturing environment.
My background is in telecom and ITE, not factory automation. However, I have
been asked to assist a client
In a message dated 7/7/99, Susan Beard writes:
Anyone know of any connectors with 0.1 spacings that survive a 2000 volt
rms hipot requirement?
Susan:
Don't forget that for most connectors, the minimum spacing actually occurs on
the printed circuit board, at the land areas around the pins.
In a message dated 7/1/99, Peter Merguerian writes:
By the way, a transformer is not always needed on a modem. The
new design of modems have capacitors (not required to be
Approved) between the TNV-3 and SELV.
Hi Peter:
It is certainly true that some of the new modem DAA devices use
In a message dated 7/1/99, George Sparacino writes:
I have a modem product that failed the hipot requirement defined in
cls 6 of 950. My understanding is that an isolation xfmr between Telco
SELV is needed and clearance from Telco gnd is to be 3mm minimum. Does
anyone have any other
In a message dated 3/24/99, jim.wi...@adtran.com writes:
The only design criteria with regard to insulation in Bellcore standards or
UL 1459 is a hi-pots test.
Creepage and clearance do not exist in traditional C.O. equipment (just look
at wire wrapped
backplanes).
Dear Jim and others:
In a message dated 98-10-12, Mel Pederson writes:
If one considers the worst case (DC) voltages that could possibly exist on
TNV-3 lines and also SELV circuits, and considers the likelihood that these
are at opposite polarity, one would obtain a worst case 180VDC = -120VDC
(TNV-3) - 60VDC
I am trying to sort out an an apparent contradiction between the main body of
the harmonized EN 60950 and the national deviations that appear in Annex ZB.
I would appreciate some assistance from the safety professionals and
regulatory experts in the emc-pstc and treg forums.
My particular problem
Judd Stewart writes:
We are currently designing an ac filter assembly. The board is extremely
small and we need to put text in etch (copper) on board. About the only
place is an area that provides basic insulation from ground.
Judd:
Would it be possible to provide your text in a (non
In a posting dated 98-02-18, Rich Nute writes:
I am assuming that the capacitors are connected between
mains and secondary circuits. (If they are connected
between a high-voltage secondary and a low-voltage
secondary, then this discussion does not apply.)
Such capacitors would be Y
In a message dated 97-08-14 02:21:07 EDT, Art Michael writes:
Have heard from some sources that surge-suppressors (Varistors, MOVs,
Tranzorbs, etc) are not allowed between Line to Ground, in EN 60950
products
Art:
A few years ago, I saw a letter on VDE or TUV letterhead that stated that
MOVs
In a message dated 97-03-19, Jerry Roberton writes the following regarding
the Blue Angel program:
Its the German environmental excellence marque.
I have heard about the Blue Angel program from a client. My client's product
is a large machine that is intended for use in commercial office
In a message dated 97-02-18, Darrell Upson writes:
Does anyone know of a source for a spread spectrum clock oscillator.
We have a sample of a 20MHz spread spectrum oscillator that we find
reduces radiated emissions readings from our products by several dB.
The company name was IMI in
In a message dated 96-07-24, Brent Taira writes:
Is anyone aware of an agency approved Y1 capacitor (IEC 384-14, 1993
edition)
that is stable at high temperatures (X7R)?
One more item - a VDE Engineer had informed me that I needed to use either 3
-
VDE 565-1 or 2 - VDE 560-2 approved capacitors
In a message dated 96-06-20, Jeff Welsh writes:
I am invovled with basic (Plain Old Telephones) that are used mostly in the
USA.
We have an inquiry to use them both in Italy and the Czech Repulblic.
Aside from the agency approvals, does anyone know what typical issues must
be adressed? I'm
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