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General discussion

internet connection not detected

Jan 15, 2011 7:05AM PST

My desktop computer (running Vista Home Basic 32bit) is unable to connect to my broadband connection through my modem (DSL 502T) and a 12m ethernet cable. It does not detect any modem or connection whatsoever and a red cross appears over the internet tray icon.

I don't think the problem lies with the cable as I'm able to connect to the web if I use the cable with an alternative modem (RTA 5020a). And I don't think it's the modem itself since it connects fine if I use the modem with a phone line extension and an alternative, shorter ethernet cable, instead of the longer ethernet cable alone (my computer is some distance from the phone jack). But obviously I want to use the ethernet cable over the phone line extension.

To further complicate things, my laptop (also w/ Vista) has no problem connecting to the internet using the original modem (DSL 502T) and long ethernet cable together.

So I'm guessing the problem lies with the system/software settings on my desktop? Device Manager shows no conflicts or alert symbols on my Network or Modem adapters.

Help!

Discussion is locked

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When faced with this one
Jan 15, 2011 7:22AM PST

I carry ethernet cards and cables with me on the call. I have to nod a lot as they want it to be some setting.
Bob

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If it isn't the NIC or the cable ...
Jan 15, 2011 9:02AM PST

which, as Bob points out are the normal problem then I would look closely at the modem itself and give it a try in the one configuration you didn't mention.

That would be 502T modem with a phone line extension and the 12m cable rather than the short cable you indicate you get a connection with.

The point being that if it connects in ANY CONFIGURATION of cable, modem, phone line, then it cannot be any software configuration at fault - it has to be hardware.

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hmmmm
Jan 15, 2011 10:19AM PST

thanks for replies guys.

Edward: I tried the configuration you mention but without any connection. I'm no expert but I 'm baffled that it could still be a hardware problem given that each individual piece (cable, modem, network adapter/computer) works fine and connects in a different configuration. As I said the modem works fine with the laptop and the desktop with the shorter ethernet cable.

But if it is a hardware problem, is there a method/application of testing which part is the faulty link? I'm on a budget and can't afford to simply replace each part until it hopefully works.

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Sadly.
Jan 15, 2011 11:40AM PST

I'd encountered NIC's that work ok on one cable but not another. The test is to swap in another card or cable. Sadly that's the cheap test today. Test gear such as Time Domain Analyzers could test the cable but most of us don't have such.

-> I didn't ask if any cable is home made.
Bob

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ok
Jan 16, 2011 3:59AM PST

Bob, thanks for your assistance. Neither of the cables is homemade.

But I have learnt that the longer ethernet cable is "crossover", while I'm not positive but assume the shorter ethernet cable (sent by ISP with the other (RTA) modem) is "straight-through". I noticed that the DSL modem manual says to use "straight-through" cable so perhaps this is the problem, even though the modem works fine with the crossover cable on the laptop. I have ordered a (longer) straight-through cable and will soon see.

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That helped.
Jan 16, 2011 8:41AM PST

Not all network cards support or deal with that. Let me share what the feature is called -> AUTO-MDX.

Here the network cards can cost the same as a cable! I've seen cards less or more than cables so for me, either is the fix.

--> If I didn't write it, mystery solved.
Bob