Re: [8023-POEP] Fwd: Open_for_ballot:_Project_Number_3-0324-B-1, proposed_creation_of_a_new_TSB Guidelines_for_Supporting_Power_Delivery_over_Balanced_Twisted-Pair_Cab ling_(if_approved,_to_be_published_as_TSB-184)

[Geoff Thompson <thompson@xxxxxxxx>]

Val-

At 09:48 AM 3/10/2009 , Valerie Maguire wrote:

> Hi Geoff: 
>
> Upon consideration of the following points, 
>
> 1) TSB-184 is an informative bulletin (there are no
> normative requirements) and it's scope is limited to,
> "the transmission and
> electrical parameters needed to support power over category 5e or better
> balanced twisted-pair cabling" 
>
> 2) While TSB-184 provides the guidance that, "Category
> 5e or higher performance cabling are recommended for new installations
> designed to support remote powering",  nowhere in the document
> does it say that category 5e is required as a minimum grade of cabling to
> support PoE Plus nor does it imply that legacy category 5 cabling
> exhibiting a DC loop resistance of 25 ohms is not sufficient to support
> the PoE Plus application 
>
> 3) Minimally compliant TIA-specified legacy category 5
> cabling can exhibit a DC loop resistance of 40 ohms

It was my understanding that the above is not the case.
Specifically:

        

All TIA
Cat 5 cabling was 25 ohm

        

Cat 3 TIA
cabling may be 40 Ohm

        

Some 11801
legacy Cat 5 cabling (metric) could be worse than 25 ohm

Best regards,

        

Geoff

I believe that the TSB-184 document content is in full harmony with the pending IEEE 802.3at draft and provides reasonable guidance to end-users looking to support power delivery over category 5e and higher grades of balanced twisted-pair cabling.  As a result, I do not support your recommendation that a liaison letter is necessary.

Kind regards - Val
 


Geoff Thompson <thompson@xxxxxxxx>
Sent by: owner-stds-802-3-poep@xxxxxxxx

03/09/2009 04:49 PM

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Geoff Thompson <thompson@xxxxxxxx>

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[8023-POEP] Fwd: Open_for_ballot:_Project_Number_3-0324-B-1, proposed_creation_of_a_new_TSB Guidelines_for_Supporting_Power_Delivery_over_Balanced_Twisted-Pair_Cab ling_(if_approved,_to_be_published_as_TSB-184)




Colleagues-

This ballot for a TSB for power delivery over UTP
calls out a higher requirement than we do for our
project. Further, their more stringent requirement
(5e) vs. our requirement (5) has nothing to do with
power delivery. The differences between 5 & 5e have
nothing to do with the DC performance of either
cabling system.

I have highlighted the area of concern on page 4 of the draft within
comment CS04

I urge that P802.3at send a liaison letter to TIA asking that the proposed
TSB change the requirement (Category 5e) to that which we call out in our
draft (Category 5) on the technical basis that PoE+ can be supported
onlegacy systems of Cat 5 cabling.

Best regards,

Geoff Thompson

>Date: Fri, 6 Mar 2009 12:08:44 -0500 (GMT-05:00)
>From: standards@xxxxxxxxxxx
>To: gthompso@xxxxxxxxxx
>Subject: =?UTF-8?Q?Open_for_ballot:_Project_Number_3-0324-B-1,_propo?=
>  =?UTF-8?Q?sed_creation_of_a_new_TSB__=E2=80=9CGuidelines_for_Suppor?=
>  =?UTF-8?Q?ting_Power_Delivery_over_Balanced_Twisted-Pair_Ca?=
>  =?UTF-8?Q?bling_=E2=80=9D_(if_approved,_to_be_published_as_TSB-184)?=
>
>Project Number 3-0324-B-1, proposed creation of a new TSB  "Guidelines for
>Supporting Power Delivery over Balanced Twisted-Pair Cabling" (if
>approved, to be published as TSB-184) is now open for ballot.
>
>For Committee(s): TR-42, TR-42.7
>
>Please vote prior to the close date of Monday, 4/6/2009.
>
>Click on this link to vote:
>https://www.tiaonline.org/standards/committees/ballots/
>
>If you are not registered to vote and would like to register to vote
>please change your voting options.
>
>If you are registered and do not want to vote please remove your name from
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>'Information Only'.
>
>If you have any questions, please reply through this email.
>
>
>Thank You
>
>Teesha Jenkins
>
>
>
>
>
>