Poe Overview - 3Com 8807 Configuration Manual

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PoE Overview

PoE on the Switch
P E C
O ONFIGURATION
3Com Switch 8800 Family Series Routing Switches (hereinafter referred to as
Switch 8800 Family series) support power-over-Ethernet (PoE). Equipped with
external power supply and PoE-capable cards, Switch 8800 Family series can
provide 48 VDC power for remote powered devices (PDs, such as IP phones,
WLAN APs, and Network cameras) through twisted pairs.
The Switch 8800 Family series support LEGACY Power Supply standard. While
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they can also supply power to PDs noncompliant with the standard.
The power supply of the Switch 8800 Family series is administered by the SRP
card; each PoE card on the switch can be viewed as a power sourcing equipment
(PSE), which administers the power supplying of all the ports on it independently.
The Switch 8800 Family series can transmit data and supply power in the mean
time through the signal lines (1, 3, 2, and 6) of the category-3/5 twisted pairs.
Using converters, they can also supply power to the PDs that can be powered only
through spare lines (4, 5, 7, and 8).
The Switch 8800 Family series supply power through the Ethernet electrical
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ports on the service cards. Each service card can supply power to up to 48
remote devices at the maximum distance of 100 m (328 feet).
The maximum power that can be supplied by each Ethernet port to its PD is
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16.8 W.
When supplying power to remote devices, the maximum total power that can
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be provided by the Switch 8800 Family series is 4500 W (220 V)/2250 W
(110V). The switch determines whether or not to supply power to the next
remote PD it discovered depending on the total power it currently supply.
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When a remote PD is powered by an Switch 8800 Family series switch, the PD
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needs not have any external power supply.
If the remote PD has an external power supply, the Switch 8800 Family series
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switch and the external power supply will be redundant with each other for the
PD.