The committee has expressed an interest in standard nomenclature to be used in presentations associated with high power PoE. Here I will present some suggested terms to be used in 802.3at. Please respond with your opinion and feedback on the best terms to use.
SUGGESTIONS:
SYSTEM
802.3at PoE: 802.3af PoE:
Type 2 PoE Type 1 PoE ***Note 1
802.3at 802.3af ***Note 2
AT PoE AF PoE
.at
PoE .af PoE
PoE+ PoE
PoE Plus PoE
PoEp PoE
HP PoE PoE
PSE
802.3at PoE: 802.3af PoE:
Type 2 PSE Type 1 PSE
802.3at PSE 802.3af PSE
.at
PSE .af PSE
AT PSE AF PSE
PoE+ PSE PSE
PoE Plus PSE PSE
PoEp PSE PSE
HP PSE PSE
PD
802.3at PoE: 802.3af PoE:
Type 2 PD Type 1 PD
802.3at PD 802.3af PD
.at
PD .af PD
AT PD AF PD
PoE+ PD PD
PoE Plus PD PD
PoEp PD PD
HP PD PD
Notes:
1. Type 1, Type 2, Type 3, etc.
This terminology was well received during the meeting in November. It should be noted that depending on the outcome of committee w!
ork,
there might be more than 2 types of PSEs, and PDs. I am referring to PSEs that can drive all 4 pair vs PSEs that drive 2 pair. If high-power PoE includes 2-pair and 4-pair PSEs, then type 1, type 2, and type 3 would be well suited. Realize there might be some early confusion because in the near term a 4-pair high power PSE might be referred to as a type 2 PSE. If 2-pair and 4-pair PSEs exist, a 4-pair PSE would probably be better termed as a type 3 PSE. Until the 2-pair/4-pair question is answered, it would be best to clarify what type of system is being referenced.
This nomenclature will also work well to help users understand which PDs will work with which PSEs. I.E. Type 1 PDs work with Type 1 and 2 PSEs. Type 2 PDs only work with Type 2 PSEs. It makes sense. If there were 3 types of PSEs and PDs, this same inter-operability tier system would work.
2. 802.3af and 802.3at
Vario!
us 802
enhancements including 802.3af have used the letter designation successfully in the marketplace and to some extent this helps advertise IEEE committee work. However, it should be noted that the features defined in the 802.3at committee eventually get folded into the 802 specification and all references to 802.3af and 802.3at are lost. It should also be remembered that the 802.3at work will result in a clause that combines both 802.3af and high power PoE systems into one section.
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CURRENT BALANCING
There are two types of current balancing that will be discussed in future committee meeting and it will help us if we use a consistent terminology to describe these two different types of balancing.
4-Pair System, Balancing current in each of the 4-pair
In a!
4-pair
system, current is delivered to the load via 2 pairs (4 conductors) on the top rail. Balancing the current in each pair on the top (or bottom) could be called:
Active Load Sharing (ALS)
Active Current Balance (ACB)
Pair-to-Pair Balancing (P2PB)
Balancing Current in the Magnetics
In either a 2-pair or 4-pair system, there may be a desire to balance the current in each of the conductors of a single pair. This balancing reduces the offset current in the magnetics and could be called:
Magnetics balancing MB)
Inter-pair balancing (IPB)