Table of Contents
Advertisement
Chapter 1: Overview
PoE Wiring
Power Budget
30
Table 4. PoE and PoE+ Powered Device Classes (Continued)
Class
3
4
The IEEE 802.3af and 802.3at standards define two methods for
delivering power to powered devices over the four pairs of strands in
standard Ethernet twisted-pair cable. The methods are called Alternatives
A and B. In Alternative A, power is supplied to powered devices on strands
1, 2, 3, and 6, which are the same strands that carry the 10/100Base-TX
network traffic. In Alternative B, power is delivered on strands 4, 5, 7, and
8. These are the unused strands.
Note
1000BASE-T cables carry the network traffic on all eight strands of
the Ethernet cable.
The twisted pair ports on the AT-IE200-6FP and AT-IE200-6GP Switches
support Alternative A. They transmit power on strands 1, 2, 3, and 6.
Consequently, they can support PDs that also support Alternative A.
PDs that comply with the IEEE 802.3af and 802.3at standards are
required to support both power delivery methods. However, non-standard
PDs and PDs that were manufactured before the completion of the IEEE
802.3af and 802.3at standards and that support only Alternative B will not
work with the switches.
The power budget is the total amount of DC power the AT-IE200-6FP or
AT-IE200-6GP Switch can supply to the powered devices on its ports.
These switches have a maximum power budget of 120W.
The number of powered devices the switch can support at one time will
depend on the switch's power budget and the power requirements of the
powered devices. As long as the total power requirements of the powered
devices is less than the power budget of the switch, the switch can supply
power to all the devices. If the total power requirements exceed the power
budget, the switch denies power to one or more ports using a mechanism
referred to as port prioritization.
To determine whether the power requirements of the PoE devices you
Maximum
Power Output
Usage
at the Switch
Port
Optional
15.4W
Optional
30.0W
PD Power
Range
6.49W to
12.95W
12.95W to
25.9W
Advertisement
Table of Contents
