cat5 and electrical fields

I'm hoping to ask the pros in this group to help me figure an unusual problem out. I have over 6 yrs experience in tpcip networking and cat5 cabling. I have a small business and cat5 network on a daily basis...

Ok with that said the problem I'm having is running a brand new cat5 cable out to my work shed on my property that is only 70 feet away from my 3com 24 port router. I already have several other workstations in the house that are plugged into the router via external wires. They are on the network and I can ping them whenever needed...

The line to my shed... I made up the wire. Tested the wire before I moved the new computer to the shed. Worked great.

Moved the new computer to the shed. hooked up the wire. Can't ping Cant Access at all...

Ok... I have to run over a 5ft chain link fence...

I've tried all of the possibilities short of digging a ditch and can not figure this out... Maybe the shed has an open electrical field??

Any Ideas...Suggestions??



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Thanks for replying Dimitri,

Grin... I'm not welding at the time that I'm cabeling... Yes The lights are on on both the nic and the router... and just incase... I have tried changing the router port to another...

I know this is screwd up but its really happening for two weeks now...

I even went so far as to buy another batch of cat5 cable. same results... Maybe the fence??

Thanks Dimitri Tim

Reply to

You said you maid up the wire, then tested. Did you mean that you installed the jack on the shed end of the cable and THEN pulled to the shed? If that's true, then you could have easily pulled a wire or two out of their IDC (punch-down) connectors.

Check to see if there is a link light on the NIC. It should usually be steady green. Check on the switch, too. If one of the link lights is missing, then one or both wires of the local end receiving or far end transmitting pair got disconnected.

It is highly unlikely that you are experiencing any EMI - related problem. Unless, of course, you are doing some arc welding AT THE SAME TIME as troubleshooting your network. Monster Garage of a shed, so to speak. If your shed is like mine and almost everybody else's then EMI is the least of your worries. CAT5E cables are balanced enough to fight all but the most extreme EMI sources.

Check the wire map.

Good luck!

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T-568A or -B?

-- Robert

Reply to
Robert Redelmeier

Both link lights on is a good sign. Since you have couple more PCs, it never hurts to verify if the link light really shows a connection to the PC you are troubleshooting ;-).

Check wiremap, I think this is where the problem is. There are couple other things you can check though:

Are the switch and the NIC capable of auto-negotiating the speed of the connection? (on older equipment) it happens that they can't come to an agreement and therefore can't connect.

You are not running a Gig Ethernet, right? Try to manually switch your NIC to 10Mbit/s, see if it fixes the problem. It's been said that 10Mbit/s Ethernet can run over barbed wire, so you might as well use that fence as a transmission medium ;-)

Were you pulling the cable too hard? Have you used any staples mounting the cable? Have you cinched the cable too tight with a tie-wrap?

90% of the cabling problems are identified by wire map testing; I keep coming back to this. Make sure you rule out simple wire map problems before you start banging your head against a fence ... I mean, a wall ;-)
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And if the wire map is correct showing all four pair connected to the correct pins at both ends of the cable, and a different computer gives the same result, then it's time to test and certifiy fhe cable. You could have a poor connection that is causing the problem. Some poor connections will pass wire map but the impedance is just to high to pass a usable signal.

Reply to
Justin Time

Maybe grounding problems with your AC power. What if a substantial current is flowing on your twisted-pair? I have seen coax knocked down by unintentional current flowing on the shield, and have installed twisted-pair to "get around" that, rather than fixing the root problem, but what if you have a worse problem than I've seen, such as 120V or so on the twisted-pair? Check that your shed is grounded back to the breaker box at the house, and your computers and switch are grounded.

- Scott

Reply to
Scott Packard

Copper Ethernet is isolated by transformers at both ends. There is no current caused by ground differentials in normal use. Lightning is a whole different story and good reason to run fiber between buildings.

Go into the properties on the ethernet card and force the settings to

10Mb/half duplex. If it works then you've damaged the cable or crimped the pins incorrectly.
Reply to
Al Dykes

Not likely. NICs are connected to twisted pair cable via transformers, which will eliminate such problems.

Reply to
James Knott

info_at_cabling-design_dot (Dmitri( wrote in news:1rn5e.7529740$

From the K.I.S.S. School Of Repair: Did you try the cable on the same computer that you moved to the shed? With the link lights active, it really seems like there is a software problem. If you tested it on the same computer, disregard.

If not: Let's get the basics, what OS you are running, configuration, etc.


Reply to
The Chairman

Did you put the RJ45s on the cable? If there is not electric, look for crimping problems.

Reply to

Assuming it isn't mispaired, the most common cause of these problems, I have had just plain bad connectors before. Some that would work when testing continuity but fail when installed in the jacks.

I believe I even had one that would turn on the link light even though one wire of a pair was connected to the wrong pin. It was enough to almost work, I could log into a remove machine and then not be able to do anything.

Check everything for proper pairing, and then for broken, loose, intermittent, or otherwise bad connections.

-- glen

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