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Re: Here's a new idea:

Please, Bob

Stop calling the pairs for ethernet as 1 & 2  It is flat out wrong!  Pair 1 is pins 4,5. Pair 2 is either pins 1,2 or 3,6 depending on whether it is T568A or T356B. Pair 3 uses the complimentary pins not used by pair 2 and finally, pair 4 uses pins 7,8. Therefore ethernet uses pairs 2 and 3. Pairs 1 and 4 are the idle pairs.

Jack Andresen
Bob Bell wrote:

 James -

The current direction of the group seems to favor the use of pairs 3 and 4 for the powering. I would personally prefer it if the powering were pairs 1 and 2 but I don't know what the final outcome will be. However, a stated goal of the group is to consider the system in relationship to the gigabit ethernet so that would require that pairs 3 and 4 still be able to be used for signals. If the powering and detection could be accomplished via a common mode method, then the results would satisfy this goal. If not, then there are complications involved.


At 11:11  5/1/2000, James M. Polk wrote:


It's Monday, so forgive this clarification, but are you asking Tal to test his scheme on the signaling pairs of a 10/100BASE connection as well as pins 4/5/7/8 on a 1000BASE-T connection? If not, I'd be curious if Tal could do this; if so.... then I'm being redundant again redundant again......

At 10:18 AM 5/1/2000 -0600, Bob Bell wrote:
>Tal -
>One of the objectives the group stated was to test for powerablity on the
>same wires as the power would be provided. In addition, it is desirable
>that the powering and thus the testing be done in such a manner that the
>signal carrying capability of the wire pairs not be compromised (this it to
>allow it to work with 1000BaseT. Could your scheme meet these two requirements?
>Bob Bell
>At 02:27  4/30/2000, Tal Weiss wrote:
>>Hi all,
>>Since this is my first contribution to the forum and I'm not sure that this
>>email forwarding system works, I'll be brief.
>>I read the different discovery process approaches and I want to offer
>>something completely different!
>>All of the proposals in the forum are analog by nature, and lack in
>>I was able to construct a digital "power-identity-chip", costing less than
>>1$, to be implemented inside the powered-IP-phone. This was done using
>>off-the-shelf parts.
>>The chip is powered remotely from the switch using 5 Volts (a simple 5K
>>pull-up resistor does the trick).
>>The power-enabled-switch polls the line for "power-identity-chip" (this can
>>be done across wires 4,5 or 7,8) and when a phone is attached the chip is
>>found (CRC protected communication, of course).
>>This chip then tells the switch what it's power requirements are! (Voltage,
>>which wires, power, MAC address and so on...)
>>The power-enabled-switch then applies the correct power using the correct
>>This approach has been tested in the lab and works using different cabling
>>schemes from more than 200 meters!
>>No false alarms and no misses.
>>I know this is different than all the other approaches mentioned above, but
>>it works so well I couldn't resist sharing.
>>If more information is needed I'll be glad to supply it!
>>Tal Weiss
>>Congruency Ltd.
>>23 Hasivim St.
>>POB 7813
>>Petah-Tikva 49170, Israel
>>Email:  tal@xxxxxxxxxxxxxx
>>Phone:  972-3-9212322-218
>>Fax  :  972-3-9210757
>Bob Bell
>Cisco Systems Inc.

"At the end of the day... the most committed win!"

 James M. Polk
Sr. Product Manager, Multiservice Architecture and Standards
Enterprise Voice Business Unit
Cisco Systems
Dallas, Texas
w) 972.813.5208
f)  972.813.5280

Bob BellCisco Systems Inc.801-294-3034(v)801-294-3023(f)