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Re: Continuous Current Capacity of Panels, Jacks, and Plugs


This proposal sounds like it is in line with the discovery proposals that
the group to be homing in on. The one item that I would take direct issue
with would be the null value. I believe that we will end up defining a
minimum, non-zero current that we will decide represents the non-connected
condition. This will be to make provision for a small amount of current to
be leaked into the TO/socket itself so that an indicator can be lit.


At 11:59 AM 2/10/00 +0100, Raymond Gass wrote:
>we have been looking at the various proposals for
>remote powering / discovery process, and we would
>like to stimulate discussion about a simplified
>the benefits of this proposal are as follows:
>- it does not introduce extra hardware in the power
>sink, and thus no extra cost in the terminal part
>- no impact on the data transmission
>- it can be used whatever choice for powering
>(phantom or direct mode, on data or on spare wires)
>the method is based on a measurement of the
>value of the current, performed by the "check
>box" associated to the power source:
>- during discovery process, a low frequency (some kHz),
>low voltage (2-3 V) is sent, that makes it possible to
>measure the line impedance (whatever line), and to
>decide if this particular line needs to be fed or not,
>based on the peak value of the AC current
>- during feeding phase, DC current is being monitored.
>Power feeding is maintained as long as DC current
>is not null. Discovery process is re-initiated when
>DC current is null
>we have prepared some slides to describe further
>this solution, and we are ready to make a presentation at the
>next 802.3 meeting
>thanks for your comments

| Geoffrey O. Thompson                    |
| Chair IEEE 802.3                        |
| Nortel Networks, Inc.  M/S SC5-02       |
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