Re: [802.3_4PPOE] Update - 4P-PoE End to End System Imbalance (Channel Pair To Pair Resistance Imbalance) Ad-Hoc Chair. - With the attachment now

["Darshan, Yair" <YDarshan@xxxxxxxxxxxxx>]

Thanks,

I understand your point.

This method was recommended in IEEE802.3 before we updated it to Type 2 systems.

It was for the pair level but the same concept apply for P2P as well. It called ballast resistors..

Yair

 

 

From: Lennart Yseboodt [mailto:lennartyseboodt@xxxxxxxxx]
Sent: Thursday, February 20, 2014 7:47 PM
To: STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_4PPOE] Update - 4P-PoE End to End System Imbalance (Channel Pair To Pair Resistance Imbalance) Ad-Hoc Chair. - With the attachment now

 

Hi Yair,

With Fast Ethernet I refer to 100BASE-TX, which only uses two pairs and hence is implemented with magnetics only on the data pairs.

I agree that adding resistors would solve the problem if done correctly on both ends of the powered cable.

Not particularly elegant though, I can image this will often be forgotten (especially at the PD side).

Kind regards,

Lennart

 

On Sat, Feb 15, 2014 at 10:09 PM, Darshan, Yair <YDarshan@xxxxxxxxxxxxx> wrote:

Thanks Lennart,

I'll at this input to the list of issues that we need to discuss.

The easy way to accommodate with this situation is to add 120/130mOhm or the relevant number to equalize the imbalance if it will cause not meeting the channel resistance unbalance spec which is TBD now.

Why you believe that fast Ethernet doesn't use magnetics? What are the frequencies of the fast Ethernet?

Yair  

 

 

From: Lennart Yseboodt [mailto:lennartyseboodt@xxxxxxxxx]
Sent: Friday, February 14, 2014 11:27 PM
To: STDS-802-3-4PPOE@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_4PPOE] Update - 4P-PoE End to End System Imbalance (Channel Pair To Pair Resistance Imbalance) Ad-Hoc Chair. - With the attachment now

 

Hi all,

The worst case numbers on page 7 list for the transformer winding resistance a range of 120mOhm to 130mOhm.

Considering Fast Ethernet devices or switches that do not implement transformers on the spare pairs the range should be 0 Ohm to 130mOhm.

Kind regards,

Lennart

 

On Fri, Feb 14, 2014 at 10:10 PM, Darshan, Yair <YDarshan@xxxxxxxxxxxxx> wrote:

Hi all,

 

Please see attached the ad-hoc material for the meeting on Monday. Feb 17, 2014.

Comments and inputs are welcome.

 

Regards

 

Yair

 

Yair Darshan

4P-PoE  End to End System Imbalance  (Channel Pair To Pair Resistance Imbalance) Ad-Hoc Chair.

 

 

Darshan Yair

 

Chief R&D Engineer

Analog Mixed Signal Group

Microsemi Corporation

 

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