Ethernet transceiver connections

Can anyone help please?

I want to run some 10/100 Ethernet with a rack between 8 or so boards 
including 1 switch device. The output from the Ethernet devices on each of 
the boards is basically an MDI i.e. after the PHYs. I don't want to include 
magnetics due to the space requirements and no need to run any distance. 
It's possible to connect PHYs together but how exactly is it done. Can they 
simply be connected directly or is capacitative coupling required?

TIA.

Roger. 

Roger schrieb:
> Can anyone help please?
> 
> I want to run some 10/100 Ethernet with a rack between 8 or so boards 
> including 1 switch device. The output from the Ethernet devices on each 
> of the boards is basically an MDI i.e. after the PHYs. I don't want to 
> include magnetics due to the space requirements and no need to run any 
> distance. It's possible to connect PHYs together but how exactly is it 
> done. Can they simply be connected directly or is capacitative coupling 
> required?
> 
> TIA.
> 
> Roger.

Roger,

This is not standardized, and from what I gather the biggest problem is 
the different voltage levels the (different?) PHYs have. Most PHY 
manufacturers have app notes on this subject which should get you 
started. I know for sure RealTek and National do.

HTH

Markus

"Roger" <enquiries@rwconcepts.co.uk> skrev i meddelandet 
news:13tab41a2sui44f@corp.supernews.com...
> Can anyone help please?
>
> I want to run some 10/100 Ethernet with a rack between 8 or so boards 
> including 1 switch device. The output from the Ethernet devices on each of 
> the boards is basically an MDI i.e. after the PHYs. I don't want to 
> include magnetics due to the space requirements and no need to run any 
> distance. It's possible to connect PHYs together but how exactly is it 
> done. Can they simply be connected directly or is capacitative coupling 
> required?
>
> TIA.
>
> Roger.

With switched Ethernet and one device per port, you could probably
replace the PHY with some LVDS transceiver.

-- 
Best Regards,
Ulf Samuelsson
This is intended to be my personal opinion which may,
or may not be shared by my employer Atmel Nordic AB