8.1 PoE Overview
This section describes the basic concepts of PoE.
Power over Ethernet (PoE) refers to power supply over a 10Base-T, 100Base-TX, or 1000Base-
T twisted pair cable. PoE can be used to effectively provide power for terminals such as IP
phones, Access Points (APs), chargers of portable devices, point-of-sale (POS) machines,
cameras, and data collection. Terminals are powered when they access the network. Therefore,
the indoor cabling of power supply need not be considered. Currently, PoE supports the unified
standard IEEE 802.3af and 802.3at, which enables devices developed by different vendors to be
compatible with each other.
8.2 PoE Features Supported by the S5700
This section describes the PoE features supported by the S5700.
The downstream electrical interfaces of the S5700 support PoE. Each downstream interface
provides a maximum of 30 W power and a maximum power supply distance of 100 m. The
S5700 can transmit current and data on the same pair of signal cables.
PoE power supplies are classified into the following types: 500 W constant current power supply
and 250 W constant current power supply. A 500 W power supply provides 369.6 W power for
the PoE function, and a 250 W power supply provides 123.2 W for the PoE function.
The following S5700 models support PoE:
l
S5700-48TP-PWR-SI and S5700-52C-PWR-EI
Each switch has two power supply slots. Each slot supports a 500 W or 250 W power
supply. When two PoE power supplies are used, determine their working mode according
to the following table.
Power Supply Combination
Available PoE Power
250 W constant current
–
123.2W
500 W constant current
–
369.6W
250 W constant current
250 W constant current
246.4W
250 W constant current
500 W constant current
492.8W
500 W constant current
500 W constant current
739.2W
l
S5700-24TP-PWR-SI and S5700-28C-PWR-EI
Each switch has two power supply slots. Each slot supports a 500 W or 250 W power
supply. When two PoE power supplies are used, determine their working mode according
to the following table.
Power Supply Combination
Available PoE Power
250 W constant current
–
123.2W
500 W constant current
–
369.6W
Quidway S5700 Series Ethernet Switches
Configuration Guide - Device Management
8 PoE Configuration
Issue 01 (2011-07-15)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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