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Long ethernet connection with problems

TFranke asked
Medium Priority
Last Modified: 2010-04-21
I am trying to join two buildings with an Ethernet cable. Distance is aprox 60 meters (180ft). On one end, I have a modem connected to a Linksys WRT54G router, and on the new building, I receive the ethernet cable in a Dlink Switch (DES-1008D) , I distribute ethernet in 6 outlets and send one cable down stairs (10 meters (30 feet)) away from the switch and receive it in another dlink switch, again a (DES-1008D). If I place a laptop at the receiving end of the ethernet cable that comes from the main building, it receives the signal (internet) ok, when I try each one of the outlets in the top floor, I receive internet ok, although the farthest I am from the switch, the longer it takes to connect. When I go down stairs, I can't connect, or it connects intermitently. I have tested all sections with a tester and they work ok. My gut feeling is that I have taken the length of the ethernet cables to the distance limit, and because of the amount of connections it has to go through, I loose some extra signal.
1st Question: Do the swithces act as range extenders amplifying the ethernet signal, or they just provide a pass through not amplifying at all.
2nd Question: Are there any signal amplifyers I might use to solve this problem?
3rd Question: Is there any other solution I might look at, or other tests I should perform?\

Because of the layout of the building it is not possible to use a wifi link.

Thank you!
Watch Question

1. Switches acet as pass through.
2. Apmplifyers exist but are expensive. 180ft should not be too long.
3. Try replacing cable with brand new one and test ends. Also try a thicker coating (I think its called plenum) in case there is some electrical interferance with the wiring in the ceiling.

I had the exact same problem except I could get a signal if I switched my nic to 10 full. Eventually I laid on the floor a new cable and just ran it thru the building and terminated both ends and tried connecting again and it seemed to work.

I hope this helps

Bernie SalvaggioIT Manager

Switches are not included in the 100m length of a single ethernet run if that's what your question was, so no worries there. However, when you go between buildings (especially) or even between floors you should be using something like fiber due to varying ground voltages between buildings/floors, which is likely what's causing your problem. If you use fiber you can just get a couple fiber to cat5 converters.


So 5 out of 6 connections in the remote work?  Why the switch downstairs - what happens if you connect a client directly to the downstairs cable.

Also,  what kind of tester did you test them with?  A pin-check is not enough to know if there is a problem.  You would want crosstalk tests at a minimum - the testers are not cheap though - I paid about 4K for mine several years ago.

It sounds like either a marginal cable to the downstairs (most likely) or a bad switch downstairs.

Switches reset the 180m limit, they don't amplify, they store and retransmit.  Hubs will work as well - cheap and chearful way, hubs are considered rubbish because they send everything out of every port.  That doesn't make a difference if you only have 2 connections though, a switch is a waste of money in this case :)  **Any more than 2 connections to a hub it should be a switch **

Most ethernet cable is UTP, unshielded, so it will be badly affected by interference such as power cables.  180m is theoretical, as is 100m for gig.  Shielded (STP) can be better, however for any real distance you should use fibre.  Your laptop probably has a better NIC and handled the errors, while the switch detected it was corrupt and dropped it for retransmission.

Also, and this is nearly impossible to calculate, you get echos (refractions) in the cable from imperfections in the copper.  This can do odd things to signals - its above my ability of physics these days - but it does happen.  Lengthening the cable, perversely, may work, as may shortening it.  Or use very expensive, high quality cable.  Maybe Cat6 even, though I am not convinced it will help.

Setting your ports to 10 half or full may help if you can put up with it, 10Mb is more tolerant that 100mb and more again than gig.


The problem was that the electrician who installed the cables, "crossed" the pairs instead of making them "straight". He even crossed them incorrectly, so what I did was to make over the male jacks, to make them similar to the female endings on the other end. I ended up with straight cables, but colors not matching the standard UTP protocol. Nevertheless, testing the ends with my own tester detected that.

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