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Re: [802.3_4PPOE] Comment 54 in D3.4



Geoff, I don’t  disagree with you, but I think the main difference in the BASE-T port types on this issue are in the style of the text.  Or is there a problem raised by the style of the clause 126 text that you see?

George A. Zimmerman, Ph.D.
CME Consulting, Inc.
Experts in PHYsical Layer Communications
310-920-3860


On Apr 29, 2018, at 5:36 PM, Geoff Thompson <thompson@xxxxxxxx> wrote:

George-

I am going to push back a little on you here.
From a system supplier point of view,
the PoE elements of an equipment port need to meet all of the emission and susceptibility requirements of the rest of the transceiver for ANY port into which it is integrated.
That means that PoE elements from suppliers need to meet the same requirements as any eligible twisted pair transceiver.

Therefore, our requirement needs to match the most restrictive text found in the eligible twisted pair transceiver texts.

Geoff


On Apr 29, 2018, at 3:39 PMPDT, George Zimmerman <george@xxxxxxxxxxxxxxxxxxxx> wrote:

Lennart - the clause you referenced is an optical clause. We should be consistent with the phy clauses that clause 145 goes with. Because clause 14 is quite old, I’d go with clauses 40, 55 and 126.

Clause 126 is the most recent - it simply says:
126.9.5 Electromagnetic compatibility
A system integrating the 2.5GBASE-T or 5GBASE-T shall comply with applicable local and national codes
for the limitation of electromagnetic interference.


George A. Zimmerman, Ph.D.
CME Consulting, Inc.
Experts in PHYsical Layer Communications
310-920-3860


On Apr 29, 2018, at 3:13 PM, Lennart Yseboodt <lennart.yseboodt@xxxxxxxxxxx> wrote:

I wasn't aware this was a piece of text present in the PHY clauses as well.

The comment remains valid though, this should not be a requirement in an interoperability spec (we don't need IEEE to remind us we need to comply with local and national codes).
Specifically I take issue with this being a requirement on the link.

The later PHY Clauses (change happened a bit later than Clause 33) realized this and changed the text to be like this:

87.9.4.1 Electromagnetic emission
A system integrating a 40GBASE-LR4 or 40GBASE-ER4 PMD shall comply with applicable local and
national codes for the limitation of electromagnetic interference.

Which makes more sense, now at least the requirement is on the device, rather than the cabling.

Therefore, we could go from something like:
The PD and PSE powered cabling link PSEs and PDs shall comply with applicable local and national codes for the
limitation of electromagnetic interference.

Kind regards,

Lennart

On Sun, 2018-04-29 at 20:44 +0000, Yair Darshan wrote:
Hi Lennart and all,
Regarding your comment 54:
I believe that we cant change it as you suggested:
 
My arguments are:
Yair:
1. It is part of Objective (implicit).
3. We need to meet local and national EMI codes for PSEs and PDs with their cables when they are powered or not.
4. The value of this text is that the common mode ripple and noise specified in Table 145-16 and Table 145-29 are not sufficient to meet EMI and much lower values are required.
5. It is specified for all IEEE systems and subsystems.
6. If the text is not clear we can clarify it but not delete it.
 
I also talked with Geoff Thompson about this comment and I am attaching his response:
 
The text that Lennart wants to fiddle with is as old as the hills, e.g. see:
14.7.3 Environment
14.7.3.1 Electromagnetic emission
The twisted-pair link shall comply with applicable local and national codes for the limitation of electromagnetic interference. 
so any change to that text will run up against the rest of 802.3
since it is precisely the same requirement as we have for twisted pair MAUs in general.
 
Yair
 

Darshan Yair

Chief R&D Engineer
Analog Mixed Signal Group
Microsemi Corporation
 
1 Hanagar St., P.O. Box 7220
Neve Ne'eman Industrial Zone
Hod Hasharon 45421, Israel
Tel:  +972-9-775-5100, EXT 210.
Cell: +972-54-4893019
Fax: +972-9-775-5111
 

E-mail: <mailto:ydarshan@xxxxxxxxxxxxx>.  

 
 

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