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Re: [802.3af] My quest for low power PSEs continues





Geoff:

As recently as 1000BASE stuff we felt it was within our jurisdiction to
require labeling:

  40.8.2 Crossover function
    ... Additionally, the MDI connector for a PHY that
    implements the crossover function shall be marked
    with the graphical symbol X.  ...

I think we can still do it, 1000BASE is not ancient history.

Personally, I would not be adverse to leaving the specification of the
format of the power rating (amps & volts, watts, horses, etc.) open ended
so that vendors who need to label for regulatory requirements could just
say it once.  If you live in a location where no regulatory agency requires
power labelling, well then we would add the burden, but then your label
should be pretty much a wide open space anyways.

Mike





Geoff Thompson <gthompso@xxxxxxxxxxxxxxxxxx> on 01/22/2003 04:33:53 PM

Sent by:  Geoff Thompson <gthompso@xxxxxxxxxxxxxxxxxx>


To:   Mike S McCormack/US/3Com
cc:   stds-802-3-pwrviamdi@xxxxxxxxxxxxx
Subject:  Re: [802.3af] My quest for low power PSEs continues


Mike-

I believe that old hands would argue that the scope of the requirements
that you uncovered was restricted to the equipment spec'd in their
respective clauses.

Ergo, 7.3.2 would be limited to 10 Mb/s and might well be overridden by
some more permissive text in other clauses, e.g.
14.8 MAU labeling
It is recommended that each MAU (and supporting documentation) be labeled
in a manner visible to the user
with at least these parameters:
a) Data rate capability in Mb/s,
b) Power level in terms of maximum current drain (for external MAUs),
c) Any applicable safety warnings, and
d) Duplex capabilities.

It was felt by then that mandatory labeling was onerous in terms of space
available on newer equipment.

geoff

At 03:28 PM 1/22/2003 -0500, Mike_S_McCormack@xxxxxxxx wrote:

>Ladies/Gentlemen:
>
>One of the persistent complaints about my request to allow small single
>port PSEs (see comments 169 and 170) is that the IEEE can not mandate
>labeling.  Well, I was casually reading the great opus and as I was
closing
>in on the first 150 pages of the spellbinding text, I notice the following
>little item:
>
>   7.3.2 Signaling rate
>     . . . To facilitate the configuration of operational
>     systems, DTE and MAU devices shall be labeled with
>     the actual signaling rate used with that device . . .
>
>My initial reaction was that this was an obvious mistake, the 802.3 group
>would never has required labeling.  While it was obviously for a good
>reason, someone must have messed up.
>
>I read on, then to my wonderment I came across:
>
>   8.4.2.2 Jacket marking
>     The cable jacket shall be marked in a color
>     contrasting with the background color of the jacket.
>     The markings shall be spaced at 2.5 m  5 cm
>     regularly along the entire length of the cable. . . .
>
>Now I was confused, our forbearers not only had committed the sin of
>labeling in good faith, but apparently they had done it to the most
mundane
>level imaginable.  With two "shall"s in adjoining sentences no less!
(Read
>after the text I quoted and you find they even request a specific color
for
>the cable, but that is just a request, not a requirement.)
>
>Well, now I was curious, what else could have been so important that the
>giants who walked the standard before us could have deemed it necessary.
>Then I found the most interesting text:
>
>   9.9.3.2 Power consumption
>     . . .
>     The FOMAU shall be labeled externally to identify
>     the maximum value of power supply current required
>     by the device when the AUI mechanical connection
>     is implemented.
>     . . .
>
>So the founding fathers thought power was so important that they required
a
>label for it.  As a matter fact, as I slogged through the rest of the
>document I discovered that when power was specified on an external
>interface, there was just as likely a specification for labeling.
>
>I therefore put forward that there is sufficient precedence within 802.3
to
>allow us to require labeling of PSE output capabilities.  If you feel that
>a label on the device is not sufficient to warn people about how much
power
>they can expect, we could also require that vendors documentation contain
>the power rating, the precedent for that is:
>
>   27.6 Repeater labeling
>     It is required that each repeater (and supporting
>     documentation) shall be labeled in a manner visible
>     to the user with these parameters:
>
>I think, if informing the user of the limitations of low wattage PSEs is a
>barrier to legitimizing them, we can force the disclosure.  Once the user
>can look on the device and see if it is suitable for their needs, what is
>to keep us from filling that need?
>
>Mike
(See attached file: C.htm)


Mike-

I believe that old hands would argue that the scope of the requirements that you uncovered was restricted to the equipment spec'd in their respective clauses.

Ergo, 7.3.2 would be limited to 10 Mb/s and might well be overridden by some more permissive text in other clauses, e.g.
14.8 MAU labeling
It is recommended that each MAU (and supporting documentation) be labeled in a manner visible to the user
with at least these parameters:
a) Data rate capability in Mb/s,
b) Power level in terms of maximum current drain (for external MAUs),
c) Any applicable safety warnings, and
d) Duplex capabilities.

It was felt by then that mandatory labeling was onerous in terms of space available on newer equipment.

geoff

At 03:28 PM 1/22/2003 -0500, Mike_S_McCormack@xxxxxxxx wrote:

Ladies/Gentlemen:

One of the persistent complaints about my request to allow small single
port PSEs (see comments 169 and 170) is that the IEEE can not mandate
labeling.  Well, I was casually reading the great opus and as I was closing
in on the first 150 pages of the spellbinding text, I notice the following
little item:

  7.3.2 Signaling rate
    . . . To facilitate the configuration of operational
    systems, DTE and MAU devices shall be labeled with
    the actual signaling rate used with that device . . .

My initial reaction was that this was an obvious mistake, the 802.3 group
would never has required labeling.  While it was obviously for a good
reason, someone must have messed up.

I read on, then to my wonderment I came across:

  8.4.2.2 Jacket marking
    The cable jacket shall be marked in a color
    contrasting with the background color of the jacket.
    The markings shall be spaced at 2.5 m 5 cm
    regularly along the entire length of the cable. . . .

Now I was confused, our forbearers not only had committed the sin of
labeling in good faith, but apparently they had done it to the most mundane
level imaginable.  With two "shall"s in adjoining sentences no less!  (Read
after the text I quoted and you find they even request a specific color for
the cable, but that is just a request, not a requirement.)

Well, now I was curious, what else could have been so important that the
giants who walked the standard before us could have deemed it necessary.
Then I found the most interesting text:

  9.9.3.2 Power consumption
    . . .
    The FOMAU shall be labeled externally to identify
    the maximum value of power supply current required
    by the device when the AUI mechanical connection
    is implemented.
    . . .

So the founding fathers thought power was so important that they required a
label for it.  As a matter fact, as I slogged through the rest of the
document I discovered that when power was specified on an external
interface, there was just as likely a specification for labeling.

I therefore put forward that there is sufficient precedence within 802.3 to
allow us to require labeling of PSE output capabilities.  If you feel that
a label on the device is not sufficient to warn people about how much power
they can expect, we could also require that vendors documentation contain
the power rating, the precedent for that is:

  27.6 Repeater labeling
    It is required that each repeater (and supporting
    documentation) shall be labeled in a manner visible
    to the user with these parameters:

I think, if informing the user of the limitations of low wattage PSEs is a
barrier to legitimizing them, we can force the disclosure.  Once the user
can look on the device and see if it is suitable for their needs, what is
to keep us from filling that need?

Mike