can an isdn surge protector be used with adsl?

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
Reply to
Chevy
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And nor would it protect the ethernet devices and PCs connected to the DSL modem. Sure, the DSL modem might act as a fuse and destroy itself before it passed the surges upstream to any other ethernet or PC equipment you have. But in those few millseconds it'd more likely just fry the whole bunch.

Reply to
wkearney99

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 > i got a second hand isdn & AC protector. my telephone works fine

Reply to
w_tom

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.

Noth>> Hmm, if you use a whole house POTS filter, and put the surge

Reply to
w_tom

ADSL signals use a higher frequency range.

If you put a filter on the protector, that will reduce its effectiveness.

Hmm, if you use a whole house POTS filter, and put the surge protector after the filter, then it would still protect all of your telephone equipment. It wouldn't protect the modem or POTS filter.

Reply to
Neil W Rickert

Likewise those that believe theory will always apply often neglect to accept reality as it's seen in the field.

While telco NIDs are indeed supposed to be properly grounded a GREAT many are not. Or are older installations that weren't installed right then either. Theory doesn't help when equipment gets fried. There is certainly a great amount of great amount of hype not supported by logic with various surge handling devices. Nothing's foolproof and a quite a lot of it is indeed junk. But it's just as stupid to use the wrong devices as it is to use nothing at all.

Reply to
wkearney99

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

D> Likewise those that believe theory will always apply often neglect

Reply to
w_tom

You will need a phone line protector that will support ADSL, due to the higher frequencies that it runs at, as others have mentioned.

Personally, I'm using an older APC UPS (BackUPS Office 500) that has phone/DSL protection with my DSL modem/router plugged into it. No degradation of my DSL line quality when in use; I tried a regular phone/surge protector and it clobbered my DSL signal.

Bob.

Reply to
Bob

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 discussi> You will need a phone line protector that will support ADSL, due to the

Reply to
w_tom

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

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Reply to
ChevyChasen

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 someth> i decided to open it up to try and understand how it works.

Reply to
w_tom

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

thanks.

C
Reply to
ChevyChasen

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

thanks.

C
Reply to
ChevyChasen

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