RE: detecting a PD disconnection event
Jerry,
I agree with you it is very basic and I am also supporting 1a, It was our
favorite option. However, in order to be covered legally we need to find a
paper that publicly distributed and demonstrating this concept.
Does any body has such publication?
Yair.
> -----Original Message-----
> From: Bachand, Jerry [SMTP:gbachand@avaya.com]
> Sent: ו, אפריל 27, 2001 9:07 PM
> To: 'Rick Brooks'; Barry Male
> Cc: stds-802-3-pwrviamdi@ieee.org
> Subject: RE: detecting a PD disconnection event
>
>
> Rick and group,
>
> I still prefer 1a.
> Since detecting a minimum current is such a basic and obvious means to
> detect a disconnect, I don't think anyone could even think of suing. (Not
> even Lucent or Avaya.) ;-)
>
> This means of detecting a disconnect has been in use for over 100yrs by
> telephone companies, worldwide, to detect the telephone on-hook condition.
>
> However, I have no problem with other means, as you mentioned, as long as
> the minimum current method can still be used.
>
> Please keep in mind, eventually there will be many other devices powered
> by
> the Ethernet, simple might give us more flexibility in the future.
>
> Regards
>
> Jerry
>
>
>
>
> Gerard E. (Jerry) Bachand
> Avaya Inc.
> 300 Baker Avenue, Suite 100
> Concord, MA 01742
>
> (978) 318-6402 Voice
> (978) 318-6402 Fax
>
> <gbachand@avaya.com>
>
> Formerly: Enterprise Networks Group
> ("Cajun" LAN Systems)
> of Lucent Technologies
>
>
>
>
> -----Original Message-----
> From: Rick Brooks [mailto:ribrooks@nortelnetworks.com]
> Sent: Friday, April 27, 2001 1:40 PM
> To: Barry Male
> Cc: stds-802-3-pwrviamdi@ieee.org
> Subject: RE: detecting a PD disconnection event
>
>
>
> Barry,
> 1a) was all of our favorites until Geoff's recent email regarding a patent
> issue.
>
> It may turn out that other methods are more cost effective when considered
> globally.
> My proposal is that more than one method could be used, not just the one
> that we have been assuming.
> My view is that we must at least consider alternative methods that do not
> use DC current sensing.
>
> thanks,
> - Rick
>
>
>
>
> -----Original Message-----
> From: Barry Male [SMTP:male@mail-nh.eng.utr.ti.com]
> Sent: Friday, April 27, 2001 10:29 AM
> To: Brooks, Rick [SC5:321:EXCH]
> Cc: stds-802-3-pwrviamdi@ieee.org
> Subject: Re: detecting a PD disconnection event
>
>
> Rick,
>
> My preference is 1a.
>
> Have the PSE disconnect if the AVERAGE value of load current is less
> than
> 10mA for a sample period of some time (say 100mSec)
>
> This averaging produces a robust detection method from the
> standpoint of
> system noise.
>
> Thanks
>
> Barry
>
> _________________________________________________________________
> Barry Male
> Senior Principal IC Designer Internet: barry_male@ti.com
> Power Management Products NH Phone: 603.429.8705
> Texas Instruments CT Phone: 860.844.8183
> 7 Continental Blvd. NH FAX : 603.424.3460
> Merrimack, NH 03054-0399 USA CT FAX : 860.844.8806
>
> On Fri, 27 Apr 2001, Rick Brooks wrote:
>
> > Just to start up another discussion, I wanted to find out how many
> people
> > would support
> > the following concept for detecting when a PD receiving power becomes
> > disconnected.
> >
> > the concept:
> > $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
> >
> > 1) The PSE is responsible for detecting when a PD receiving DTE power
> > becomes disconnected.
> > If that event occurs, the PSE must turn off the power within some time
> frame
> > (100ms to 500ms ballpark?)
> >
> > 2) The PSE may use any of the following methods to detect this PD
> disconnect
> > event.
> >
> > a) the DC load current drop below "X" ma (10ma?)
> >
> > b) the ethernet link has dropped out
> >
> > c) another proven method (pending discussion and feasibility
> proof)
> > some suggestions:
> > 1) the AC probing circuit detects when the AC load changes
>
> > (opens)
> > 2) the PD modulation heartbeat current ceases
> > 3) the PD response to a given PSE code is wrong or absent
> > 4) other ideas
> >
> > $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
> >
> >
> > Please voice your opinions on this concept.
> > The motivation here is to lower the cost of delivering DTE power.
> >
> > thanks,
> > - Rick
> >
> >
>