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 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:
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
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
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
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
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
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
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
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
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
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
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)
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
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
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
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
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.
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