Huawei S2750, Hardware Description

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2.3.5 Power Supply Configuration
PoE Power Supply Configuration
In the S2750-EI series, the S2750-20TP-PWR-EI-AC, S2750-28TP-PWR-EI-AC, and
S2751-28TP-PWR-EI-AC are PoE models. All the three models use internal AC power modules.
The internal power modules of the S2750-20TP-PWR-EI-AC and S2750-28TP-PWR-EI-AC
provide 370 W of PoE power, sufficient for full PoE power supply (IEEE 802.3af) on 16 and
24 ports respectively or full PoE+ power supply (IEEE 802.3at) on 12 ports. The internal power
modules of the S2751-28TP-PWR-EI-AC provide 124 W of PoE power, sufficient for full PoE
power supply on 8 ports and full PoE+ power supply on 4 ports.
Figure 2-9 shows the PoE power supply connections on the switches. After AC power is
transmitted to the PWR module on the switch, the PWR module provides a channel of 12 V
voltage and a channel of -53 V voltage. The 12 V voltage is provided for the entire device, and
the -53 V voltage is provided for the PDs.
Figure 2-9 PoE power supply by AC power modules
Motherboard
GND 12V
PWR
L N PGND
-53V RTN
L: Live wire N: Neutral wire PGND: Protective ground
wire
GND: 12 V reference
ground RTN: -53 V reference
ground
Non-PoE Power Supply Configuration
The non-PoE models in the S2750-EI series use internal power modules and do not support
pluggable power modules.
Figure 2-10 shows the power supply connections on the non-PoE models. An internal AC power
module (PWR) receives power from an external power source and provides a 12 V output to the
chassis.
S2750 Series Ethernet Switches
Hardware Description
2 Chassis
Issue 04 (2014-03-20) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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