Re: [8023-POEP] [802.3] Interpretations received since March IEEE 802 Plenary meeting
As I recall, we discussed this at some length in the
af meetings. Doesn't seem to have helped, as the text
is still broken. I suspect this text came right from
the data portion of the standard, where isolating the
RJ45 from the PHY is feasible.
I'd recommend the PSE text be modified to resemble the
PD text - I can't think of any reason why we'd care
where the actual isolation barrier is, as long as
ground loops are prevented and humans can't touch the
line potential.
See you all in San Francisco -
Dave Dwelley
ddwelley@xxxxxxxxxx
--- Yair Darshan <YairD@xxxxxxxxxxxxxx> wrote:
> I agree with Mike with his response.
> No additional comments.
>
> Yair
>
>
> Darshan Yair
> Chief Engineer
> PowerDsine Ltd. - Powering Converged Networks
> 1 Hanagar St., P.O. Box 7220
> Neve Ne'eman Industrial Zone
> Hod Hasharon 45421, Israel
> Tel: +972-9-775-5100, Cell: +972-54-4893019
> Fax: +972-9-775-5111
> E-mail: <mailto:yaird@xxxxxxxxxxxxxx>.
> <http://www.powerdsine.com>
> -----Original Message-----
> From: owner-stds-802-3-poep@xxxxxxxx
> [mailto:owner-stds-802-3-poep@xxxxxxxx] On Behalf Of
> McCormack, Michael
> Sent: Monday, May 23, 2005 6:59 PM
> To: STDS-802-3-POEP@xxxxxxxxxxxxxxxxx
> Subject: Re: [8023-POEP] [802.3] Interpretations
> received since March
> IEEE 802 Plenary meeting
>
> David et al.
>
> With specific regard to interpretation request
> 1-07/05;
>
> Q1: I believe that the specification is clear and
> unambiguous with
> regard to the need for isolation and the location of
> the isolation
> barrier and as such requires no further action other
> than to state this
> to the enquirer.
> Q2: I find that this is a request for consultation
> for a particular
> implementation, this should be returned as such.
> Q3: Again, this is a request to interpret the
> standard in view of a
> particular implementation, and appears to me to be a
> request for
> consultation and as such should be returned.
> Q4: Once again, consultation for a particular
> implementation and should
> be returned.
>
> All this aside, I believe that the standard is
> flawed because, while the
> standard is complete and unclear, it is also quite
> unworkable. Section
> 33.4.1 which reads:
> "The PSE shall provide electrical isolation between
> the
> PI device circuits, including frame ground (if
> any), and
> all PI leads."
> asks for an isolation barrier where a DC path must
> clearly exist. The
> specification for the PD,
> "The PD shall provide electrical isolation between
> all
> external conductors, including frame ground (if
> any),
> and all PI leads."
> is much more appropriate. As you pointed out and
> was discussed at this
> week's PoE Plus interim, we need to address this and
> repair the standard
> as soon as practical. I will plan to make time
> available during the PoE
> Plus meetings during the plenary week to address
> this issue that goes
> well beyond the limited scope of an interpretation
> meeting.
>
> Cheers
>
> Mike
>
>
>
>
>
> Michael McCormack
> Texas Instruments, Power Interface Products
> 50 Phillippe Cote St.
> Manchester, NH 03101 USA
>
> Voice: +1 603 222 8686
> Fax: +1 603 222 8580
> Email: mike_mccormack@xxxxxx
> Web Site: http://www.ti.com
<snip>
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