Re: Continuous Current Capacity of Panels, Jacks, and Plugs
Raymond-
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.
Geoff
At 11:59 AM 2/10/00 +0100, Raymond Gass wrote:
>Geoff,
>
>we have been looking at the various proposals for
>remote powering / discovery process, and we would
>like to stimulate discussion about a simplified
>solution.
>
>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
>
>Raymond
|=========================================|
| Geoffrey O. Thompson |
| Chair IEEE 802.3 |
| Nortel Networks, Inc. M/S SC5-02 |
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