[vdr] Re: LAN cable length / Streaming Plug-In

[Maarten van den Berg <maarten@ultratux.net>]

On Friday 04 April 2003 13:24, Steffen Koch wrote:
> vete.ran@gmx.de wrote:
> >>For the connection, I use two 'normal' CAT 5 cables (20m + around 10m
> >>for a network outlet/box = 30m) connected to a 20m cross-over CAT 5
> >>cable. Directly connecting the both PCs with the 20m cross-over cable
> >>gives a perfect picture, but then, the cable is visible in the whole
> >>stairway :-(. Connecting the two 20m cables with an network cable
> >>adapter already causes blocks and interruptions, but not as much as
> >> if I use the complete connection over 50m.

That is precisely your problem; you cannot (I repeat: CANNOT) use adapters 
to extend cat5 for ethernet purposes.  If you use 1 (one) cable instead 
of your 3 or 4 extended cables all your troubles will be over. 
Yes, really.

> > I think it's a cable lenght problem.

Impossible. You are using cat5 , right ?  The cable length for ethernet is 
somewhere like max. 130 m from node to hub or 180(?) m total from any 
node to any other node.  Your cable is way shorter than that.

> > When installing cables at my home i have some cables over 30 Meter.
> > I had to correct the connectors. Twisted Pair is not twisted enough
> > for lenght over 20 Meters so you have to turn some cables.

Sorry, but this is just utter crap.  Cat5 is Cat5. It has more twists per 
length than Cat3, amongst other differences. There is NO such thing as a 
"not quite twisted enough" cat5 cable. Then, it just wouldn't be cat5.

> can't be. TP with 10/100/1000MBps is specified for cables up to 100
> meters. I have Gigabit Ethernet (over copper) running @home with cables
> up to 60 meters running perfectly giving a throughput of approx. 70
> MB/s via IP.

Exactly.

> >>How can I avoid these problems? Is the reason for the problems the
> >>overall cable really the length of around 50m? Does a switch help
> >>'amplifying' the signal? Or can there be transmission errors that are
> >>not corrected by the used UDP protocol (caused by other cables near
> >> to the LAN cable)?

Using hub or switches instead of "extenders" would help, sure. But not 
because the signal is amplified, as such. It's because extenders are not 
meant for ethernet (only ISDN etc.) One extender plus the two plugs that 
are needed make such a big 'gap' in the 'twistedness' that there is so 
much interference that the signal is vastly deteriorated. That is all.
Lose the extenders and use hubs or, preferably, one uninterrupted cable.

Maarten

-- 
This statement is either false or a paradox.


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