William Chops Westfield wrote:

> On Oct 21, 2005, at 1:55 PM, Wouter van Ooijen wrote:
> 
>>> You cannot send ethernet over 1km
>>
>>
>> not electrically, but surely fiber should do the trick?
>>
> The main reason for not allowing more than 1km of ethernet has to
> do with retaining the ability to detect collisions in a timely
> manner.  For something one-directional like UDP video, you MIGHT
> be able to get away with longer distances (but electrical issues
> will show up sooner or later; I'm pretty sure that to go even 1km
> you're supposed to invoke several "repeaters" (which never caught
> on much, thankfully!)  If you have power along the way, you can
> insert arbitrary numbers of bridge/switch type boxes...

You can now get POE (power over ethernet) switches (which are
basically repeaters when only two ports are connected).

R

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