 |
Search Sci.Electronics.Basics |
|
|
|
|
|
|
 |
|
|
Sci.Electronics.Basics -> Surge / Ground / Lightning
There are 215 messages in this thread.
You are currently looking at messages 200 to 215.
|
Author: krwDate: 19:28 08-05-08
|
|
In article <OKadnRdUKpg42L7VnZ2dnUVZ_tPinZ2d@comcast.com>,
me@nomail.com says...
> bud-- wrote:
> > Mike Tomlinson wrote:
> >> In article <76535$4821baa0$4213eb20$7766@DIALUPUSA.NET>, bud--
> >> <remove.budnews@isp.com> writes
> >>
> >>> Phone wires were clamped to ground before the 1960s?
> >>
> >> It was common to earth one leg of the incoming pair to either the house
> >> ground or to its own rod. An earth connection also allowed "party
> >> lines", where two houses could share one physical phone line pair,
each
> >> house with its own number. Disadvantage was that both lines could not
> >> be used simultaneously.
> >>
> >> http://en.wikipedia.org/wiki/Party_line_(telephony)
> >>
> >> My previous house still had its telephone earth rod and earth wire,
> >> though it had not been connected to the phone line for many years.
> >>
> >
> > I am pretty sure we had a party line long ago when I was a kid.
> > Wikipedia's reference to "20th century telephone systems" makes me
feel
> > even older.
> > One side of the ringer is all that was connected to earth.
> >
> > Not clamping phone wires to earth is a major surge suppression flaw. It
> > allows high voltage from phone to power wires (like at a modem), and
> > increases the stress on a multiport plug-in suppressor. A service panel
> > suppressor doesn't help the voltage difference at all.
> >
> > Surprising since the UK seems to be very good on electrical protection
> > in general.
> >
> I had a party line as a 10 year old. I used to screw with the other
> party if I heard them when I picked up the phone.. strange noises, etc.
> Of course I got caught, corporal punishment, etc.
We had a party line when I was very young. ...until about '56, or
so. Ma Bell had gotten rid of them in the area by '59.
> I think they used to ring between the red green for one party, yellow
> green for the other party, black green, etc.
No, that would defeat the purpose of the party line. The ringers
either had "distinctive ring" (once for Mabel, twice for Maude) or
were frequency tuned.
--
Keith
|
|
|
|
Author: w_tomDate: 22:26 08-05-08
|
|
On May 8, 1:07 pm, fl_fly_...@yahoo.com wrote:
> Is the Joule rating of an SPD important?
> While conceptually an surge protection device (SPD) with a larger
> energy rating will be better, comparing SPD energy (Joule) ratings can
> be misleading. More reputable manufactures no longer provide energy
> ratings. The energy rating is the sum of surge current, surge
> duration, and SPD clamping voltage.
> In comparing two products, the lower rated device would be better if
> this was as a result of a lower clamping voltage, while the large
> energy device would be preferable if this was as a result of a larger
> surge current being used. There is no clear standard for SPD energy
> measurement, and manufacturers have been known to use long tail pulses
> to provide larger results.
MOV manufacturers do not play the 'joules' games that some plug-in
protector manufacturers play. Plug-in protector typically uses as
little or less than 1/3rd and never more than 2/3rds of rated joules
during protection. During some surges, a plug-in protector may use 0%
of its joules because the massive surge voltage is same on all wires -
as surge seeks earth ground destructively via electronics. No voltage
between wires means the protector never sees any of the destructive
surge - does nothing for protection. So how many joules does it
really use?
An effective 'whole house' protector uses 100% of its joules for all
types of surges which is why 'whole house' protectors can routinely
earth direct lightning strikes without damage - why these protectors
suvive and absorb less energy due to an exponentially longer life
expectancy.
Joules that actually get used during each surge provide a ballpark
measurement for a protector's life expectancy. Further numbers are in
an above reply to VWWall on 7 May 2008.
SVR, typically 330 or 400 volts, printed on the box, required by the
UL, and more often called "let-through voltage". A vague number so
that consumers can make ball park comparisons. No useful for making
engineering decisions.
A plug-in protector rated at 330 volts will start conducting at
maybe 200 volts. When a larger surge occurs, it conducts at 900
volts. Protector rated at 330 volts conducts between 200 and 900
volts. What happens when conducting at or above 900 volts? MOV self
destructs - vaporizes. Also called those 'scary pictures' - what every
MOV manufacturers defines as unacceptable operation.
So what does that SVR (threshold or let-through) voltage really
measure?
Discussed is a 70 SVR difference. Irrelevant since the difference
between ineffective and proper earthing is thousands of volts. If not
properly earthed, then even a tiny 100 amp surge puts that protector
at something approaching 12,000 volts. 70 volts or even 330 volts is
completely irrelevant.
Properly routed ground wire (no sharp bends, etc) can make
thousands of volts difference as described by so many professional
citations. What defines protection? Quality of and connection to
earth ground can make thousands of volts difference.
Page 42 Figure 8 from Bud's IEEE citation. Will a 330 or 400 volt
protector make any difference? Of course not. With either protector,
that surge is still >8000 volts destructively finding earth ground
through an adjacent TV. How to eliminate up to 12,000 volts?
Shorten the 50 feet AC electric wire between protector and earth
ground to zero feet.
Bud posts that electronics contain internal protection of 600 or 800
volts. Intel ATX specs demand that internal protection exceed 1000
volts. Just another reason why 330 or 400 let-through volts is
irrelevant. Relevant is 900 volts during a typically destructive
surge on a 330 or 400 volt protector.
"My surge protector sacrificed itself to save my computer".
Reality. A protector was so grossly undersized that voltage exceeded
900 volts. MOV did what no MOV must do - vaporize. What protected
that computer? Computer's internal protection protected the
computer. But a naive computer assembler *knows* the protector
provided protection. A myth promoted by grossly undersizing plug-in
protectors. To be effective, a protector must earth a direct
lightning strike and remain functional.
Why argue over which jelly bean is prettier when the room will be
engulfed by a flood. 70 volts difference in SVR is trivial when
improper earthing can mean another 8000 or 12,000 volts during the
typically destructive type of surge.
|
|
|
|
Author: w_tomDate: 22:52 08-05-08
|
|
On May 8, 12:11 pm, bud-- <remove.budn...@isp.com> wrote:
>> UL makes no effort to measure a protector's protective ability.
> Cuttler Hammer says you are wrong.
> http://tinyurl.com/63594d
Again Bud misrepresents what professional say. Cutler-Hammer says:
> 2. Surge Test. Let through voltage tested at lower current
> than 1st edition. 10 kA (IEEE Cat C3) used for the first
> time, however, it was used only to see if products fail
> safely.
Only tests a product for a safe failure =96 does not threaten human
life. Does not measure the performance of protection. Same citation
further states:
> 2. UL does not verify that the TVSS device will achieve
> the manufacturer's published surge current ratings.
Of course not. That would be measuring a protector's protection
abilities. UL does not measure protection - in direct contradiction
to what Bud posts. A protector can completely fail during UL1449
testing and still be approved. UL only cares that is completely fails
=96 provides no effective protection =96 without threatening human life.
UL does determine functionality. Otherwise an empty box would be
submitted by Bud=92s peers as a surge protector and get UL1449
approval. A protector must demonstrate some protector function. But
UL makes no effort to measure abilities of that protector. UL only
tests that it functions like a protector and does not harm humans.
Bud must deny those which is why his post again lies about what Cutler-
Hammer, IEEE, NIST, and so many others say.
Meanwhile, Bud repeatedly claims that protectors create fires
because UL1449 was created in 1998. UL1449 was approved in 1987 as
Cutler-Hammer also says. Again, Cutler-Hammer disagrees with what
Bud posts. Numerous plug-in protectors after 1998 with UL approval
still create a fire risk =96 the scary pictures:
http://www.hanford.gov/rl/?page=3D556&parent=3D554
http://www.westwhitelandfire.com/Articles/Surge%20Protectors.pdf
http://www.ddxg.net/old/surge_protectors.htm
http://www.zerosurge.com/HTML/movs.html
http://tinyurl.com/3x73ol
http://www3.cw56.com/news/articles/local/BO63312/
Finally, Bud claims a plug-in protector protects from a surge
that typically destroy appliances. 400 times Bud has been asked to
provide those specs. He refuses because no plug-in manufacturer will
claims what Bud posts. Bud lies about his own IEEE, NIST and Cutler-
Hammer citations. Bud even claims that UL measures a protector's
protection abilities. UL does not. UL addresses threats to human
safety. Protector can completely fail during UL testing and still be
approved as long as the protector does not spit flame during that
failure.
Bud provides not one manufacture spec that claims protection. Bud
cannot provide what does not exist. No wonder Bud will also post
insults He cannot dispute facts even from his IEEE, NIST, and Cutler-
Hammer citations. A protector is only as effective as its earth
ground. UL makes no effort to rate protection for each protector.
|
|
|
|
Author: Mike TomlinsonDate: 01:17 09-05-08
|
|
In article <72ae0$48232b9a$4213eac2$18448@DIALUPUSA.NET>, bud--
<remove.budnews@isp.com> writes
>Not clamping phone wires to earth is a major surge suppression flaw.
It's simply not necessary in towns and cities in the UK. Occurrences of
damage caused by surges on phone lines are practically unheard of.
There are reports of damage caused by direct or nearly lightning
strikes, but of course nothing is going to protect against that.
Houses in villages and remote locations would probably benefit most from
additional protection. You can be sure that critical installations
(hospitals, data centres, etc.) will install additional protection.
British Telecom fit NTE (network termination equipment), also known as a
master socket, which does have surge arrestors built in, but they don't
clamp to earth, they're just across the line:
http://www.buzzhost.co.uk/nte5.php
has a circuit diagram of the NTE, and an interesting photo of damage
caused by a direct lightning strike further down the page (which, of
course, none of w_'s equipment would have prevented.)
An additional factor is that adding further surge protection devices can
affect the line characteristics, causing ADSL sync speeds to drop.
> A service panel
>suppressor doesn't help the voltage difference at all.
Obviously.
>Surprising since the UK seems to be very good on electrical protection
>in general.
As I said in an earlier post, a calm, intelligent assessment (not w_'s
level of hand-waving, gibbering hysteria) of each situation is needed
before deciding on the level of protection required.
It's clear that it's simply not needed for most UK domestic phone lines;
this will have been borne out by years and years of experience, looking
at the number of insurance claims, etc. I should think BT's attitude is
that if the customer wishes to install additional protection after the
demarc (NTE), that's up to them.
In the end, It's all about assessing risk and mitigating it.
I found this webpage rather amusing:
http://www.satcure.co.uk/tech/phonesurge.htm
but will leave it to others to comment :)
--
(\__/) Bunny says NO to Windows Vista!
(='.'=) http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.html
(")_(") http://www.cypherpunks.to/~peter/vista.pdf
|
|
|
|
Author: TantalustDate: 11:10 09-05-08
|
|
"Mike Tomlinson" <mike@jasper.org.uk> wrote in message
news:jYz7iLNG69IIFwOj@jasper.org.uk...
> In article <72ae0$48232b9a$4213eac2$18448@DIALUPUSA.NET>, bud--
> <remove.budnews@isp.com> writes
>
>>Not clamping phone wires to earth is a major surge suppression flaw.
>
> It's simply not necessary in towns and cities in the UK. Occurrences of
> damage caused by surges on phone lines are practically unheard of.
> There are reports of damage caused by direct or nearly lightning
> strikes, but of course nothing is going to protect against that.
>
> Houses in villages and remote locations would probably benefit most from
> additional protection. You can be sure that critical installations
> (hospitals, data centres, etc.) will install additional protection.
>
> British Telecom fit NTE (network termination equipment), also known as a
> master socket, which does have surge arrestors built in, but they don't
> clamp to earth, they're just across the line:
>
> http://www.buzzhost.co.uk/nte5.php
>
> has a circuit diagram of the NTE, and an interesting photo of damage
> caused by a direct lightning strike further down the page (which, of
> course, none of w_'s equipment would have prevented.)
>
> An additional factor is that adding further surge protection devices can
> affect the line characteristics, causing ADSL sync speeds to drop.
>
>> A service panel
>>suppressor doesn't help the voltage difference at all.
>
> Obviously.
>
>>Surprising since the UK seems to be very good on electrical protection
>>in general.
>
> As I said in an earlier post, a calm, intelligent assessment (not w_'s
> level of hand-waving, gibbering hysteria) of each situation is needed
> before deciding on the level of protection required.
>
> It's clear that it's simply not needed for most UK domestic phone lines;
> this will have been borne out by years and years of experience, looking
> at the number of insurance claims, etc. I should think BT's attitude is
> that if the customer wishes to install additional protection after the
> demarc (NTE), that's up to them.
>
> In the end, It's all about assessing risk and mitigating it.
>
> I found this webpage rather amusing:
>
> http://www.satcure.co.uk/tech/phonesurge.htm
>
> but will leave it to others to comment :)
>
> --
> (\__/) Bunny says NO to Windows Vista!
> (='.'=) http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.html
> (")_(") http://www.cypherpunks.to/~peter/vista.pdf
>
Wow, it says phone lines there can have as much as 180 [ringing] volts on
them, interesting.
|
|
|
|
Author: bud--Date: 13:30 09-05-08
|
|
w_tom wrote:
> On May 8, 12:11 pm, bud-- <remove.budn...@isp.com> wrote:
>>> UL makes no effort to measure a protector's protective ability.
>> Cuttler Hammer says you are wrong.
>> <URL deleted>
>
> Again Bud misrepresents what professional say.
Sorry I picked up the wrong URL. The correct one is
http://tinyurl.com/5m3wrf
> UL does not measure protection - in direct contradiction
> to what Bud posts.
Using the correct URL, the CH cite above says suppressors have to remain
functional through an initial set of surges (20 surges - 6kv, 3kA). That
is significant functionality.
They can fail safely after that. (Although CH does not say it, I believe
the test for plug-in suppressors is at a lower current.)
> A protector can completely fail during UL1449
> testing and still be approved.
It can fail after significant functionality (above) has been
established. For instance when subjected to long overvoltage a
suppressor can fail safely.
>
> Meanwhile, Bud repeatedly claims that protectors create fires
> because UL1449 was created in 1998.
w_ is so stupid he still can’t figure out the difference between a
creation date and a revision date.
UL1449-2ed (1998) requires thermal disconnects.
> UL1449 was approved in 1987 as
> Cutler-Hammer also says. Again, Cutler-Hammer disagrees with what
> Bud posts.
With minimal intelligence w_ could read in old link "UL1449(2nd edition
1996 [publication date])".
In the new link, 1st sentence: "The Second Edition of UL1449 became
effective August 17, 1998."
> Numerous plug-in protectors after 1998 with UL approval
> still create a fire risk – the scary pictures:
Lacking valid technical arguments, w_ continues to lie about scary pictures.
None of the links say a damaged suppressor even had a UL label.
Still missing - a link to any source that says UL listed plug-in
suppressors made after 1998 are a problem.
> A protector is only as effective as its earth
> ground.
w_'s religious mantra will protect him from evil.
Still missing - a link to another lunatic that says plug-in suppressors
are NOT effective.
Still missing – answers to embarrassing questions:
- Why do the only 2 examples of surge suppression in the IEEE guide use
plug-in suppressors?
- Why does the NIST guide says plug-in suppressors are "the easiest
solution"?
- Why do all but one of w's "responsible manufacturers" make plug-in
suppressors?
- Why does SquareD say in addition to their "whole house" suppressors
"electronic equipment may need additional protection" from plug-in
suppressors.
- Why aren't airplanes crashing daily when they get hit by lightning (or
do they drag an earthing chain)?
For reliable information read the IEEE and NIST guides. Both say plug-in
suppressors are effective.
--
bud--
|
|
|
|
Author: bud--Date: 13:40 09-05-08
|
|
w_tom wrote:
>
>Plug-in protector typically uses as
> little or less than 1/3rd and never more than 2/3rds of rated joules
> during protection.
Depends on the surge that arrives. Like a service panel suppressor, buy
one with adequate ratings.
>
> An effective 'whole house' protector uses 100% of its joules for all
> types of surges
Depends on the surge that arrives.
>
> A plug-in protector rated at 330 volts will start conducting at
> maybe 200 volts. When a larger surge occurs, it conducts at 900
> volts.
Large surges can hit service panels so you might get 900V at the
service. The significant impedance of a branch circuit for surges
greatly limits the current that can reach a plug-in suppressor. Many
sources recommend adding a plug-in suppressor at "sensitive"
electronics to further limit the service panel let-through voltage.
>
> Bud posts that electronics contain internal protection of 600 or 800
> volts. Intel ATX specs demand that internal protection exceed 1000
> volts.
bud quotes Martzloff who says 600-800V.
> Just another reason why 330 or 400 let-through volts is
> irrelevant.
As usual, w_ can’t understand Martzloff. Voltage let-through is
important to Martzloff because the lowest values cause suppressors to
conduct on surges that are not damaging to connected equipment, which
shortens the lifetime of the suppressor.
>
> "My surge protector sacrificed itself to save my computer".
> Reality. A protector was so grossly undersized that voltage exceeded
> 900 volts.
In w_'s mind, plug-in suppressors have minuscule ratings, service
panel suppressors have mega ratings. Plug-in suppressors are readily
available with very high ratings for relatively low cost.
And w_ only buys special MOVs that self destruct at 900V. All the others
depend on energy absorbed.
> MOV did what no MOV must do - vaporize.
w_ buys also only buys unlabeled Chinese suppressors that do not have
the UL required thermal disconnect.
Still can't find another lunatic that says plug-in suppressors are NOT
effective?
--
bud--
|
|
|
|
Author: bud--Date: 13:53 09-05-08
|
|
krw wrote:
> In article <OKadnRdUKpg42L7VnZ2dnUVZ_tPinZ2d@comcast.com>,
> me@nomail.com says...
>>> Mike Tomlinson wrote:
>>>>
>>>>> Phone wires were clamped to ground before the 1960s?
>>>> It was common to earth one leg of the incoming pair to either the house
>>>> ground or to its own rod. An earth connection also allowed "party
>>>> lines", where two houses could share one physical phone line pair,
each
>>>> house with its own number. Disadvantage was that both lines could not
>>>> be used simultaneously.
>>>>
>>>> http://en.wikipedia.org/wiki/Party_line_(telephony)
>>>>
>> I think they used to ring between the red green for one party, yellow
>> green for the other party, black green, etc.
>
> No, that would defeat the purpose of the party line. The ringers
> either had "distinctive ring" (once for Mabel, twice for Maude) or
> were frequency tuned.
>
They did frequency and distinctive rings. But for 2 parties you can ring
red-to-ground for one and green-to-ground for the other. It is in Mike's
Wikipedia link above. My recollection is black was ground and yellow was
sometimes used for a light in the phone (red and green are phone wires).
--
bud--
|
|
|
|
Author: krwDate: 22:33 09-05-08
|
|
In article <bc45f$48248dbc$4213ea37$25354@DIALUPUSA.NET>,
remove.budnews@isp.com says...
> krw wrote:
> > In article <OKadnRdUKpg42L7VnZ2dnUVZ_tPinZ2d@comcast.com>,
> > me@nomail.com says...
> >>> Mike Tomlinson wrote:
> >>>>
> >>>>> Phone wires were clamped to ground before the 1960s?
> >>>> It was common to earth one leg of the incoming pair to either the
house
> >>>> ground or to its own rod. An earth connection also allowed
"party
> >>>> lines", where two houses could share one physical phone line
pair, each
> >>>> house with its own number. Disadvantage was that both lines could
not
> >>>> be used simultaneously.
> >>>>
> >>>> http://en.wikipedia.org/wiki/Party_line_(telephony)
> >>>>
> >> I think they used to ring between the red green for one party, yellow
> >> green for the other party, black green, etc.
> >
> > No, that would defeat the purpose of the party line. The ringers
> > either had "distinctive ring" (once for Mabel, twice for Maude) or
> > were frequency tuned.
> >
>
> They did frequency and distinctive rings. But for 2 parties you can ring
> red-to-ground for one and green-to-ground for the other. It is in Mike's
> Wikipedia link above. My recollection is black was ground and yellow was
> sometimes used for a light in the phone (red and green are phone wires).
Princess phones used the yellow green pair for the dial light. A
transformer was hidden somewhere in teh house to supply the power
(IIRC, a standard 24VAC door bell transformer, but it's been a lot
of years).
--
Keith
|
|
|
|
Author: Michael A. TerrellDate: 00:33 10-05-08
|
|
krw wrote:
>
> Princess phones used the yellow green pair for the dial light. A
> transformer was hidden somewhere in teh house to supply the power
> (IIRC, a standard 24VAC door bell transformer, but it's been a lot
> of years).
The lamp was on yellow & black. Red & Green are the pair to the CO.
--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.
Michael A. Terrell
Central Florida
|
|
|
|
Author: krwDate: 18:30 11-05-08
|
|
In article <482525B3.3AC27A9E@earthlink.net>,
mike.terrell@earthlink.net says...
> krw wrote:
> >
> > Princess phones used the yellow green pair for the dial light. A
> > transformer was hidden somewhere in teh house to supply the power
> > (IIRC, a standard 24VAC door bell transformer, but it's been a lot
> > of years).
>
>
> The lamp was on yellow & black. Red & Green are the pair to the CO.
<slap!> There I was typing, looking at bud-'s post and *STILL* got
the wires crossed. I *shoulda* had a V8.
--
Keith
|
|
|
|
Author: Michael A. TerrellDate: 21:27 11-05-08
|
|
krw wrote:
>
> In article <482525B3.3AC27A9E@earthlink.net>,
> mike.terrell@earthlink.net says...
> > krw wrote:
> > >
> > > Princess phones used the yellow green pair for the dial light. A
> > > transformer was hidden somewhere in teh house to supply the power
> > > (IIRC, a standard 24VAC door bell transformer, but it's been a lot
> > > of years).
> >
> >
> > The lamp was on yellow & black. Red & Green are the pair to the
CO.
>
> <slap!> There I was typing, looking at bud-'s post and *STILL* got
> the wires crossed. I *shoulda* had a V8.
No big deal. Do you remember that wall wart being the first one
recalled for being a fire hazard?
--
http://improve-usenet.org/index.html
Use any search engine other than Google till they stop polluting USENET
with porn and junk commercial SPAM
If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm
|
|
|
|
Author: Jim RedelfsDate: 08:15 12-05-08
|
|
In article <MdKdnQNUvK94AbrVnZ2dnUVZ_hKdnZ2d@earthlink.com>,
"Michael A. Terrell" <mike.terrell@earthlink.net> wrote:
> Do you remember that wall wart being the first one
> recalled for being a fire hazard?
That was one of Western Electric's first uses of a third-party supplier.
In this case, it was Ault Manufacturing.
The Ault transformer recall was HUGE.
There are still MANY Western Electric dial-light transformers in service
to this day. Virtually all are powering NOTHING but have not been
unplugged.
--
:)
JR
|
|
|
|
Author: Michael A. TerrellDate: 15:43 12-05-08
|
|
|
|
|
|
Author: Tzortzakakis DimitriosDate: 12:21 15-05-08
|
|
Ï <phil-news-nospam@ipal.net> Ýãñáøå óôï ìÞíõìá
news:fvljt71h38@news4.newsguy.com...
> In alt.engineering.electrical "nobody >"
<usenetharvested@aol.com> wrote:
> | phil-news-nospam@ipal.net wrote:
> |> In alt.engineering.electrical Timothy Daniels
> <SpamBucket@nospamplease.biz> wrote:
> |>
> |> | Would you please sum up what you believe to be prudent
> |> | protection (for electronic equipment) from nearby lightning strikes?
> |> | I'm thinking of both in single-family homes and in condo/apartment
> |> | buildings. What would you do to protect from in-house (or
> in-building)
> |> | surges, such as elevator motors suddenly shorting out, or welding
> |> | equipment in use?
> |>
> |> How much money are you willing to spend?
> |>
> |
> | The only thing I can think of that comes close is to have a heavy
> | motor/generator set with a HUGE flywheel sitting in the basement.
>
> How about driving a generator in the basement with either a heavy
> fiberglass
> axle rod driven at some distance by a (sacrificial) motor, or by a fluid
> that
> does not conduct electricity through a turbine system, similarly driven by
> a
> motor/pump at some distance.
>
Or a compelete diesel-hydraulic locomotive? (Diesel-hydraulic coupling,
Dieselhydraulische in german)?
--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr
NB:I killfile googlegroups.
|
|
|
|
|
|
|
|
|
Contact | Electronic Portal
|
|
|
