Re: DTE Problem Set

[Mike_S_McCormack@xxxxxxxxxxx]

Unfortunately, I can't tell you what equipment uses what termination
techniques.  At the time at which I was collecting information, I went
through semiconductor application notes and collected as many varied types
of terminations as possible.  I then further enquired with 3Com engineers
and engineers at the IEEE meetings to expand the list of "known"
terminations.  I should state that the compilation only represents what I
have been able to identify, as 802.3 places no requirements, except pin to
GND isolation, designers are free to do what ever they want and probably
anything you can imagine shipped at some point in time.  With that said,
all terminations except for A (which may have also been used, but less so)
are the terminations found on various 100BASE-T ports.

As to shorting the pairs together, one termination technique that I have
not included, but probably should have, is the 1000BASE-T, which basically
shorts the two wires of the pairs together (at least from DC point of
view.)

I have copied the DTE study group on my reply because, while we are not
going to encourage proprietary systems, I feel it is important the group
know what is going on out there.  Also, while the two plus year schedule
for producing a standard may not fit in your time frame, I would encourage
you to follow what we are doing so that you stand at least a chance of
still calling your equipment "802.3 Ethernet" once the standard is
finished.







"Mike White" <mikewhite99@xxxxxxxx> on 02/02/2000 07:19:16 PM

Sent by:  "Mike White" <mikewhite99@xxxxxxxx>


To:   Mike S McCormack/US/3Com
cc:
Subject:  DTE Problem Set




Hi Mike,
I'm with a company called VitalCom that specializes in medical telemetry
systems within hopitals.
We are developing a proprietary system that we will interconnect via
Ethernet and are planning on using power distributed over  UTP.
I happened across the IEEE working group studying this same problem. There
is large amount of pertinent information there. Unfortunatly we are going
to have to release within 6 months and it doesn't look like the group is
far enough along for us to use a proposed standard.
We are planning on putting VCC on the 4-5 pair and return on the 7-8 pair.
I was going through your "DTE Power Problem Set and Solution Methodology"
slide set dated Nov 1999.
Can you tell me what equipment or who uses the Bob Smith termination shown
in slide Termination Type B and the one in Type C?
I was considering shorting the pairs ends together and was wondering what
the precedent is out there for doing this, especially in the Ethernet
world.
Thanks for any help that you can give me.
I can be contacted at:
mike_white@xxxxxxxxxxxx
800-955-2424 x4106
http://www.vitalcom.com

Hi Mike,

I'm with a company called VitalCom that specializes in medical telemetry systems within hopitals.

We are developing a proprietary system that we will interconnect via Ethernet and are planning on using power distributed over  UTP.

 

I happened across the IEEE working group studying this same problem. There is large amount of pertinent information there. Unfortunatly we are going to have to release within 6 months and it doesn't look like the group is far enough along for us to use a proposed standard.

 

We are planning on putting VCC on the 4-5 pair and return on the 7-8 pair.

 

I was going through your "DTE Power Problem Set and Solution Methodology" slide set dated Nov 1999.

 

Can you tell me what equipment or who uses the Bob Smith termination shown in slide Termination Type B and the one in Type C?

 

I was considering shorting the pairs ends together and was wondering what the precedent is out there for doing this, especially in the Ethernet world.

 

Thanks for any help that you can give me.

 

I can be contacted at:

 

mike_white@xxxxxxxxxxxx

800-955-2424 x4106

 

http://www.vitalcom.com