[Coco] [off-topic] cabling problems

[Aaron Wolfe]

On Tue, Apr 17, 2012 at 9:56 AM, Paulo Lindoso <paulo.lindoso at gmail.com> wrote:
> Hi List,
>
> It's completely off-topic, but since it seems there are a few Electronic
> Engineers in the list, I hope you can shed some light here...
>
> I have installed a Cat6 cable between two extremes at my place to build a
> network bridge.  The cable extends itself for about 60m (that 180ft
> roughly), which means it's  well within Ethernet parameters (100m,
> right?)...
>
> The problem is: when tested with a standard wire tester (for electrical
> connectivity), it passes; when you hook it to a router on one end and a
> computer on the other, it doesn't work. It doesn't pick up an IP address
> through DHCP and even if I force an IP within the network range, traffic
> doesn't flow.  On my Mac, it shows it is "Connected", but nothing happens...
>
> I have changed plugs (cut the ends, re-wired with new RJ45), router and
> tested with a different computer to no avail... so I am really at a loss,
> here...
>
> Can any of the EEs in the "house" shed me some light or give me any hint?
>  Is there any other Ethernet limitation I am not aware?
>
> Thanks for any help!
>
> Paulo

Even in extreme lengths that do exceed the spec by a good bit, I've
only seen ethernet cables that caused lots of errors (corrupt packets,
retransmissions, phantom collisions, etc).  I've not seen complete
failure to communicate.  As Marc mentioned,  neon ballasts can wreck
havoc, but again that presents itself as frequently mangled data, not
no data ever in my experience.

You mentioned "network bridge".  I am not sure what that indicates
about how things are set up, but I think I'd suspect higher layer
issues before cabling if it passes a tester.