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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@xxxxxxxxx]
> Sent:	ו, אפריל 27, 2001 9:07 PM
> To:	'Rick Brooks'; Barry Male
> Cc:	stds-802-3-pwrviamdi@xxxxxxxx
> 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@xxxxxxxxx> 
> 
> 	Formerly: Enterprise Networks Group 
>  ("Cajun" LAN Systems) 
> of Lucent Technologies 
> 
> 
>  
> 
> -----Original Message-----
> From: Rick Brooks [mailto:ribrooks@xxxxxxxxxxxxxxxxxx]
> Sent: Friday, April 27, 2001 1:40 PM
> To: Barry Male
> Cc: stds-802-3-pwrviamdi@xxxxxxxx
> 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@xxxxxxxxxxxxxxxxxxxxxx] 
> Sent:   Friday, April 27, 2001 10:29 AM 
> To:     Brooks, Rick [SC5:321:EXCH] 
> Cc:     stds-802-3-pwrviamdi@xxxxxxxx 
> 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@xxxxxx 
> 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 
> > 
> > 
>