[clug] 100 base t

Alex Satrapa grail at goldweb.com.au
Wed Nov 22 03:11:55 GMT 2006


On 20 Nov 2006, at 19:44, Adrian Blake wrote:

> Questions regarding the physical part of 100 Base t connection:
>
> Voltage levels are 0.6 V   to 2 V  yes/no

I expect this would be covered by IEEE 802.3, which is a rather  
expensive tome that I do not have access to.

> A network switch sends pulses of differing widths to automatically  
> determine the speed of the network connection, what are those  
> widths and what does it expect in return?

http://en.wikipedia.org/wiki/Autonegotiation - a reasonably technical  
article, indicating the timings and tolerances required for  
autonegotiation to succeed. This should be of use to your optical  
extender project.

> How does a switch determine if it is a full duplex or half duplex  
> connection?

This is part of autonegotiation.

> I am trying to construct a very basic but working electrical/ 
> optical media converter. I wish to avoid using a complex chip which  
> acts as a repeater, i.e reframing, timing etc. I need to keep the  
> costs down.

Is it really going to be cheaper to do this yourself rather than  
invest in an off-the-shelf component that will only cost $200? This  
assumes that you're avoiding the complex chip solution for cost  
rather than technical issues, but a typical "industrial" application  
suitable for most dirty indoor environments might be: http:// 
www.alloy.com.au/products/rnconfmx.html

Alex



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