LAN problems - Electronic Circuits Projects Diagrams Free

Tha_Wizard · 21st January 2004, 08:26 PM

Me and 4 friends of mine bought a Switch(8-Port Fast Ethernet Switch from Edimax

), cables, etc. and built a Network.
We use CAT5 UTP cable. Two of them are about 90 meters long, and the others arround 20-30 meters.
The problem is that the switch keeps getting fried. It works for a couple of months, and then it breaks. Sometimes one of the network cards also breaks. It usualy happens when it rains or snows. We changed 6 or 7 of them until now.
Somebody said it could be static electricity or electromagnetic interference.
Do you have any ideea what could be the problem and how to fix it?

elec_lover · 21st January 2004, 09:21 PM

Hi, I am working in networking services. It is not the rain or snow but lightning that cause broken ports. My experience: In a case were 2 network devices are connected together with a long cable, the port can get defective at both sides of the cable. I suppose: When there is lightning there is a high electrostatic charge in the aire causing an voltage on the cables wich is to high and damages the ports. I know that there are modems with protection to such an charge. Maybe there exist protection plugs, I don't know. Maybe a shielded cable can help ( shield to ground).
More difficult to install , an iron pipe ?

Tha_Wizard · 22nd January 2004, 08:15 PM

Could you explain me how to shield the cable to the ground? And what's the ideea with the iron pipe? 10X

Someone Electro · 25th January 2004, 12:36 PM

The idea is to put the calbe inside a metal pipe and the grund the pipe.So if a litning wod strike the pipe wod sink avey the voltege from the cable and protecting the sensetive didital electronic.

Someone Electro · 25th January 2004, 12:38 PM

O and lithing must not produce a to strong magnetic feild.becose then it froms a transformer (Pipe primari ,cable secundari)

bogdanfirst · 25th January 2004, 04:49 PM

you need to connect the shield of the cable to the computer case. do this with another wire, and connect the wire with a connector to one of the screws of your case.
BUT,
if your computer and the others are not well grounded, and a ground loop forms....this is bad. because current starts to flow from one grounding to the other. this is a common problem in network cabling.
also, keeping the cable closer to the ground, it makes it more protected.
also, the lenght of the cable is almost at the limit(100m). this means that from the EMI and RFI the signal arrives at the other end in not so high quality. are there any sources around the cable that can create strong EMI or RFI? power transformers, radio stations...etc....

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21st January 2004, 08:26 PM	(permalink)
Tha_Wizard	LAN problems Me and 4 friends of mine bought a Switch(8-Port Fast Ethernet Switch from Edimax ), cables, etc. and built a Network. We use CAT5 UTP cable. Two of them are about 90 meters long, and the others arround 20-30 meters. The problem is that the switch keeps getting fried. It works for a couple of months, and then it breaks. Sometimes one of the network cards also breaks. It usualy happens when it rains or snows. We changed 6 or 7 of them until now. Somebody said it could be static electricity or electromagnetic interference. Do you have any ideea what could be the problem and how to fix it?

21st January 2004, 09:21 PM	(permalink)
elec_lover	Hi, I am working in networking services. It is not the rain or snow but lightning that cause broken ports. My experience: In a case were 2 network devices are connected together with a long cable, the port can get defective at both sides of the cable. I suppose: When there is lightning there is a high electrostatic charge in the aire causing an voltage on the cables wich is to high and damages the ports. I know that there are modems with protection to such an charge. Maybe there exist protection plugs, I don't know. Maybe a shielded cable can help ( shield to ground). More difficult to install , an iron pipe ?

22nd January 2004, 08:15 PM	(permalink)
Tha_Wizard	Could you explain me how to shield the cable to the ground? And what's the ideea with the iron pipe? 10X

25th January 2004, 12:36 PM	(permalink)
Someone Electro	The idea is to put the calbe inside a metal pipe and the grund the pipe.So if a litning wod strike the pipe wod sink avey the voltege from the cable and protecting the sensetive didital electronic. __________________ Il give you shocking experience.

25th January 2004, 12:38 PM	(permalink)
Someone Electro	O and lithing must not produce a to strong magnetic feild.becose then it froms a transformer (Pipe primari ,cable secundari) __________________ Il give you shocking experience.

25th January 2004, 04:49 PM	(permalink)
bogdanfirst	you need to connect the shield of the cable to the computer case. do this with another wire, and connect the wire with a connector to one of the screws of your case. BUT, if your computer and the others are not well grounded, and a ground loop forms....this is bad. because current starts to flow from one grounding to the other. this is a common problem in network cabling. also, keeping the cable closer to the ground, it makes it more protected. also, the lenght of the cable is almost at the limit(100m). this means that from the EMI and RFI the signal arrives at the other end in not so high quality. are there any sources around the cable that can create strong EMI or RFI? power transformers, radio stations...etc....