Re: [802.3_4PPOE] Reflected voltage

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Hi Lennart,

Please see my inputs in the attached file or below.

Main issues:

145.2.10.3a Reflected voltage

When a 4-pair capable PSE provides power in 2-pair mode, whereby two pairs are connected to the positive

VPSE, and one pair is connected to the negative VPSE, a single-signature PD may reflect a voltage of up to

VPSE back onto the unpowered pairset. See 145.3.8.8. The PSE shall not source a current higher than Irev, as

defined in Table 145–20, on the negative pair of a pairset when the voltage of that pairset is equal to or lower

than the voltage of the other pairset.

Issues:

1. Irev is not defined in Table 145-20. – Suggest deleting link to Table 145-20. I don’t see how it help and I only see it add confusion.

2. The PSE alternative that is not powered, can't source current. It is now passive element and serves as a load so it draws current.

3. This text allows to draw >Irev if the voltage is higher than the other pairset. Delete this part.

Propose to change the whole sentence to: “The unpowered PSE alternative shall not draw a current higher than Irev, on the negative pair of the unpowered pairset.”

145.3.2 PD PI

. . .

A PD shall meet the requirements of detection (145.3.4), PD signature configuration (145.3.5), and PD classification

(145.3.6) in any valid 2-pair configuration, as defined in Table 145-20.

NOTE—this includes configurations with two pairs connected to the positive VPD and on pair connected to the negative

VPD.

I suggest that this note will be a text that explains what is 3-pair config and will be move to below Table 145-20 where it addressed.

And last:

In 145.3.5 PD signature configurations

to change from 10.1V to 21V. Need more discussions to confirm/keep this.

Yair

From: Lennart Yseboodt [mailto:lennart.yseboodt@xxxxxxxxxxx]
Sent: Thursday, May 17, 2018 10:10 PM
To: STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: [802.3_4PPOE] Reflected voltage - baseline v240

EXTERNAL EMAIL

Hi folks,

I've incorporated Heaths changes to PD signature and added the PD requirements for 3-pair.

Please check carefully - I really want to avoid making changes as this is presented next week.

We have a habit of doing that, and it frequently leads to mistakes.

Kind regards,

Lennart

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Re: [802.3_4PPOE] Reflected voltage - baseline v240