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Re: [8023-POEP] Endspan on Alt-B?

Hi all,

 

Endspan can use Alt A and Alt B and Midspan only Alt B. This is correct.

However all vendors that I am aware of are using using ALT A only in Endspan from the following reasons:

  1. To support Power + Data on the same 2P for 10/100BT applications for complete PoE solution i.e. PD gets power and data on the same physical wires allow optimum control of pre and post standard (802.3af) devices.  
  2. Some installations are using only 2P cable hence it is the only choice left.

 

Formally (Formally=in terms 100% tight proof situation) it may complicate our plans but practically very very low probability to happen so I would recommend to table this point and continue with our plans from yesterday meeting..

 

Yair

 

From: owner-stds-802-3-poep@xxxxxxxx [mailto:owner-stds-802-3-poep@xxxxxxxx] On Behalf Of Steve Robbins
Sent: Thursday, June 08, 2006 4:31 AM
To: STDS-802-3-POEP@xxxxxxxxxxxxxxxxx
Subject: [8023-POEP] Endspan on Alt-B?

 

Guys,

 

Someone just pointed out to me that an endspan PSE can use Alt-A, Alt-B, or both.  (See paragraph 33.2.1)  I had forgotten about this, assuming endspans were always Alt-A.

 

This would seem to complicate our plans to have endspans and midspans share the load.  Midspans always use Alt-B, so they can share ONLY if the endspan uses Alt-A.

 

Does anyone know of any endspans that actually use Alt-B (the spare pairs)?  If so, please reply.

 

Steve