|Thread Links||Date Links|
|Thread Prev||Thread Next||Thread Index||Date Prev||Date Next||Date Index|
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.
Bob Bell wrote:
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:BobBob BellCisco Systems Inc.801-294-3034(v)801-294-3023(f)
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:
>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?
>At 02:27 4/30/2000, Tal Weiss wrote:
>>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
>>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!
>>23 Hasivim St.
>>Petah-Tikva 49170, Israel
>>Fax : 972-3-9210757
>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