How does a power surge reset a modem?

Question

Yesterday, there was a huge power surge in my area, and I wasn't able to connect to the internet any more.

The reason was that the Wifi modem was somehow automatically reset to its factory configuration. I had to reset it to my settings today to get it working again.

Is this a normal thing? How does it happen?

Your poor poor modem. I cannot give a concise answer, but I can tell you that your device did not enjoy it. — Kortuk, Nov 22 '10 at 16:35
It could be worse. http://www.flickr.com/photos/xtl/4072175061/ — XTL, Nov 23 '10 at 10:45

score 11 · Answer 1 · answered Nov 22 '10 at 16:35

11

Often what happens in this sort of situation is not that the surge resets the configuration, but that it's sufficient to flip one bit of the configuration, such that a checksum then fails and the software decides to reset all the config to its factory settings.

Basically, high voltages push high currents, and fast-changing high currents can induce current in adjacent conductive objects, which can create the right conditions for the very tiny and delicate structures which make up non-volatile memory to change state.

answered Nov 22 '10 at 16:35

1

That is about what I would have said also. – Kortuk Nov 22 '10 at 16:39
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That is my guess as well. – Kellenjb Nov 22 '10 at 17:38
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Good lesson to learn here for those that design electronics, a check-sum probably just allowed a product to save itself from non-standard behavior. – Kortuk Nov 22 '10 at 17:56
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Yes, better to return to a known-good configuration instead of one of dubious quality that may cause problems. – Nick T Nov 22 '10 at 22:43

How does a power surge reset a modem?

1 Answers1