DComTalk.com

Chevy · Guest

i got a second hand isdn & AC protector. my telephone works fine
connected to it but my pc doesnt connect when i try with adsl.

is there any difference between adsl and isdn signals which could be
related to this problem?does the protector need its own inline filter?

thanks

c

Neil W Rickert · Guest

ChevyChasen@yahoo.com (Chevy) writes:

wkearney99 · Guest

w_tom · Guest

First, the ISDN protector is doing nothing effective IF it
does not make a 'less than 10 foot' connection to the same
earth ground used by cable and AC electric.

Second many such protectors use components with too much
capacitance (cheaper priced). They are not really selling
protection. They are profiting greater on junk science myths
such as 'surge protector = surge protection'. Protector's
capacitance that does not noticeably effect POTS service can
adversely effect the radio frequencies of ADSL (as another has
so accurately posted).

Third, the telco already provides a 'whole house' protector
inside the premise interface (NID) that makes an important
'less than 10 foot' connection to earth ground. First learn
how protectors are but one component of a surge protection
'system'. Then learn which utility is the most common source
of surge damage. Those who recommend phone line protectors
don't even know of first sentence in this third paragraph.

Chevy wrote:

w_tom · Guest

Electricity does not work as was implied. First electricity
passes through everything in a circuit. Only then does
something or many things in that circuit fail. Fuses don't
stop destructive transients. Destructive transients can
destroy and terminate in microseconds. Fasting acting fuses
take milliseconds to even consider acting. Modems do not act
as fuses. Hundreds of consecutive transients could pass
through a fuse before the fuse even considers blowing. These
are electrical principles as basic as the first electrical
class.

Nothing stops, filters, or blocks destructive transients.
Some actually believe a surge protector will stop, block,
absorb, or filter what miles of sky could not? Yes, myth and
ignorance of basic electrical concepts is that widespread.
Effective protection never stops or filters a surge.
Protectors do as Ben Franklin demonstrated in 1752 (lightning
rods). Surges are shunted - not stopped. Therefore effective
protectors are also called shunt mode devices. A surge
protector is only as effective as its earth ground.

wkearney99 wrote:

wkearney99 · Guest

w_tom · Guest

And so we now know that the NID must be properly grounded.
Without both theory and experience (as I have posted), one
would instead suffer damage and not immediately blame the
reason for that failure: the human who failed to install and
properly earth a 'whole house' protector.

Yes some phone installations are not properly earthed. And
some installations are not upgraded with the properly earthed
premise interface. Still the unearthed ISDN protector does
nothing effective.

Experience demonstrates that fuses provide no effective
protection, and that a surge passes through everything in a
circuit before anything is damaged. Unfortunately, many only
with experience would claim a knotted wire is effective
protection. Experience without underlying theory is better
called junk science. More accurately posted was

Bob · Guest

Chevy wrote:

w_tom · Guest

Telco already installs a protector for free. If the
building has been properly earthed, then that protector - also
good for ADSL - is earthed to the same ground used by cable,
AC electric, and satellite dish. The single point earth
ground is THE most critical and essential component of a surge
protection 'system'.

Where is protection in that APC UPS? Lets start with its
joules rating. To be equivalent to a minimally sized 'whole
house' protector, that UPS should be at least 3000 joules.
Look for yourself. How many joules in that APC UPS? Maybe
345?

Lets assume the 345 joule APC UPS can withstand two same
sized surges. Then the properly installed and minimally sized
whole house protector would survive about 300 same sized
surges. Why do they charge so much more for the APC UPS (tens
of times more money per protected appliance) and so grossly
undersize it? They are not claiming protection from a
typically destructive surge. And now they have you
recommending ineffective protection. Just start with the
numbers? How many joules?

Since it has no dedicated earthing, the UPS manufacturer
simply avoids the concept. No earth ground means no effective
protection. Surge protector is only as effective as its earth
ground - which is why 'whole house' protector provided the
protection that APC would rather we did not discuss. One
example sold in Home Depot is Intermatic IG1240RC. Numerous
other 'whole house' protectors are available.

Telco already installs a 'whole house' protector for phone
lines. The other and more common source of destructive surges
requires home owner action - AC electric.

APC would rather we did not have this discussion. You have
those joule numbers. Damning numbers. Too few joules to
claim protection from the type of surge that does not
typically exist. And so they have you believing it also
protects from the typically destructive surge. They got you
to *assume* protection that they do not even claim to provide.

Bob wrote:

Guest

i decided to open it up to try and understand how it works.
below are some small photos i took of the inside.

from my limited understanding of electronics the top part is for the
power protection and the lower part for the telephone line
protection.the blue components (looks like a cap & has the lettering
X1Y2 CE472M on it) normally do not conduct but on excessive current
will fuse and shunt current to earth prong.

what is the name of the blue component?how can i tell how sensitive it
is ?

thanks
C

http://geocities.com/chevychasen/circuit1_.JPG 28k
http://geocities.com/chevychasen/unit_.JPG 16k
http://geocities.com/chevychasen/circuit2_.JPG 51k
http://geocities.com/chevychasen/circuit2parts_.JPG 56k

w_tom · Guest

The three yellow components would be the MOVs. Probably
about 70 or 100 joules each. Actual value would be 1/3rd of
the protectors rated joules value. MOVs connect same as MOVs
do inside power strip protectors.

The two blue parts would be capacitors to shunt high
frequency noise to the safety ground. They must never short.
The same parts would also be inside power supplies.

Based upon the labeling, those green barrels would be three
terminal gas discharge tubes. However, to reduce capacitance
(which is so destructive to broadband signals), the protector
also uses reversed biased diodes. This device should not
cause DSL failure IF the diodes and GASx devices are not
shorted. Confirm this with a multimeter.

Nothing in this unit should fuse to provide protection.
Every component should appear as an open circuit to the
multimeter in continuity mode except diodes that should appear
as 0.7 volts in one direction and open circuit in the other.

Notice how PC traces are laid out for safety. To get a
connection from AC mains to phone line, the connection must
pass through the safety ground trace. Very important aspect
of the design.

Resistor should read something like 100K ohms. Neon light
should work when unit connect to AC mains. Even if safety
ground does not exist, the neon light should still glow.

ChevyChasen@yahoo.com wrote:

Guest

thanks for all your replies
this was an interesting trip inside this surge protector..

thanks.

C

Guest

thanks for all your replies
this was an interesting trip inside my surge protector..

thanks.

C