[SI-LIST] Gigabit Ethernet Magnetics

Hello all!

I have two questions about 1000BASE-T Gigabit Ethernet Magnetics:

1) Transformer configuration
----------------------------
There are at least 3 configurations which are commonly used. Some use
one, two or even three transformers per pair.

Is it a price/performance trade-off?

Which configuration should be used in which application? My application
would be a Gigabit Ethernet switch. I couldn't find this information
from the manufacturers.

2) Transformerless Ethernet
---------------------------
Why is a transformer actually required?

I have read information that AC coupling with a 0.1uF ceramic capacitor
also works (as in Fiber Channel, Infiniband, etc.).

The only reason I can see is the 1500V isolation. Is this a regulatory
requirement? Why is this requirement not imposed on Infiniband, etc.?


I am new to this field. Any information is appreciated.

Is there a good book, or papers, or web pages which would be helpful to
me?

Best regards,
  Martin

-- 
Enclustra GmbH                   Email: heimlicher // enclustra \\ com
Martin Heimlicher                Phone: +41 43 3431943
Wibichstrasse 10                 Fax:   +41 43 3431944
CH-8037 Zurich, Switzerland      Mobile:+41 79 2798183
 

------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List technical documents are available at:
                http://www.si-list.org

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: