Arkadiy, George did not say it wasn’t a good idea to have informative annexes - he said we are late in the process and anything we add needs to be fully fleshed out and hopefully peer reviewed. The downside is adding something that then requires more review
stretches out the process. There are other avenues to publish this material, EA being one example. For BT, the EA published a white paper where the BT editorial team tried to translate the standards language into plain English.
But to your presentation, I too have made a spreadsheet to calculate all the details of each node. Michael Paul has a simulator that we’ve correlated such that I have confidence in my spreadsheet. In my spreadsheet, I brute force calculate each node. To find
the mixing segment current, I enter the cable resistances, the MPD power, guess a current (similar to your method but you're guessing final PD voltage), and then I use goal seek to find what mixing segment current gives me zero current out the last node. For
the Type 0 one, I get 1.06 A on the mixing segment (1.06245, so not 1.07 like you have), and my initial MPD voltage is 17.48V with the final MPD voltage of 16.12V. So we are slightly off. Even if I make the current 1.07 A in my sheet, I get 16.08 V at the
last MPD.
For Type 1, my MPSE current is 1.741 A and my last MPD voltage is 36.03 V. Again, we are slightly off.
Before I’d agree to publish anything, I’d want to figure out why our numbers don’t better match. Yes, they are close but it appears one of us has an error. I was hoping Michael could pull numbers from his sim to be the tie breaker. I’m happy to send you my
spreadsheet if you want to look it over to see how our two methods might differ. (And to have a call to explain how my spreadsheet works).
From: George Zimmerman <george@xxxxxxxxxxxxxxxxxxxx>
Date: Monday, October 27, 2025 at 10:01 PM
To: Arkadiy.Peker@xxxxxxxxxxxxx <Arkadiy.Peker@xxxxxxxxxxxxx>
Cc: STDS-802-3-SPMD@xxxxxxxxxxxxxxxxx <STDS-802-3-SPMD@xxxxxxxxxxxxxxxxx>, Chad Jones (cmjones) <cmjones@xxxxxxxxx>, vmaguire@xxxxxxxx <vmaguire@xxxxxxxx>, michael.paul@xxxxxxxxxx <michael.paul@xxxxxxxxxx>
Subject: Re: Closing Remaining Comments - R1-28
Thank you!
Sent from my iPhone
On Oct 27, 2025, at 6:59 PM, Arkadiy.Peker@xxxxxxxxxxxxx wrote:
Hi George,
Thanks a lot for your fast response and feedback. We have informative annexes in POE IEEE802.3bt and I thought it would be good to have such annexes in .da standard too. I will work on a text and will try to send you tomorrow.
Best Regards
Arkadiy
From: George Zimmerman <george@xxxxxxxxxxxxxxxxxxxx>
Sent: Monday, October 27, 2025 8:29 PM
To: Arkadiy Peker - C32058 <Arkadiy.Peker@xxxxxxxxxxxxx>; STDS-802-3-SPMD@xxxxxxxxxxxxxxxxx; cmjones@xxxxxxxxx; vmaguire@xxxxxxxx
Cc: Michael.Paul <Michael.Paul@xxxxxxxxxx>
Subject: RE: Closing Remaining Comments - R1-28
EXTERNAL EMAIL:
Do not click links or open attachments unless you know the content is safe
Arkadiy – thank you for forwarding this. However, to include an informative annex, we will need text to include. While the tables are useful, and can be posted in the project area of the website to inform future users of the
standard, inclusion in the standard requires a bunch of work to make these into a proper annex. 802.3da is fairly advanced in the process now, so the inclusion of a new informative annex needs to be relatively straightforward and with minimal room for editorial
error in order to avoid prolonging the standard’s progress by multiple cycles, taking the work of many people…
Do you have text?
George Zimmerman, Ph.D.
President & Principal
CME Consulting, Inc.
Experts in Advanced PHYsical Communications
george@xxxxxxxxxxxxxxxxxxxx
310-920-3860
Hi All,
I attached presentation for calculation of voltage and current of 16 segments in multidrop system. I am proposing to add information on pages 8 and 10 to Informative annex of IEEE802.3da standard. Information on others pages
is for illustrative purposes and may or may not be added to the annex based on presentation review and comments.
Please let me know if you have any questions.
Best Regards
Arkadiy
EXTERNAL EMAIL:
Do not click links or open attachments unless you know the content is safe
All – I encourage you to use the reflector to close the remaining comments. I will start a thread on each. This one is for R1-28.
Comment R1-28 requested an annex for examples of how the mixing segment power parameters would be derived, relative to Table 189-1.
During discussion, the editor had recommended rejecting because there was no content provided, and insufficient detail to understand what was intended to convey in the annex.
The commenter offered that he had text to propose.
The next action is for the commenter to provide this text so that others can review it. Preferably, this could be supplied to the reflector or the the chair shortly so that people can review it prior to the meeting. (having to
consider it blindly during the meeting is not desirable). Responding with a PDF to this reflector email would help us all.
George Zimmerman, Ph.D.
President & Principal
CME Consulting, Inc.
Experts in Advanced PHYsical Communications
george@xxxxxxxxxxxxxxxxxxxx
310-920-3860
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