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

[Raymond Gass <Raymond.Gass@xxxxxxxxxxxxxxxxxx>]

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