3.3 Making PoE Connections

This section describes how to make a connection between a PSE port and a PoE PD device. For the PoE switch model, Port 2, Port 3, Port 4 and Port 5 are equipped with PoE PSE function. The ports are enabled to deliver power together with network signal to a connected powered device via Cat.5 cable.

To make a PoE connection, the following check points should be noted:

1.For safety reason, the connected PoE PD (Powered Device) must be a IEEE 802.3af-compliant device. Incompliant devices are not supported by the PoE switch model.

2.The Cat.5 cables used for the connections must be 4-pair cables. The power is sent over the spare pairs (4,5) (7,8) of the cable. The maximum distance supported is 100 meters.

3.The DC IN power voltage supplied to the switch must be within the following range to make PoE function working.

DC IN voltage range for PoE applications : +43V ~ +54V

4. The DC IN power supplied to the switch must meet the following calculation:

DC IN power = Sum of all connected PD power required + 3 watts

The PSE ports are equipped with the following capabilities:

1.Detection for an IEEE 802.3af compliant PD.

2.No power is supplied to a device which is classified non-IEEE 802.3af complaint PD.

3.No power is supplied when no connection exists on the port.

4.The power is cut off immediately from powering condition when a disconnection occurs.

5.The power is cut off immediately from powering condition when overload occurs.

6.The power is cut off immediately from powering condition when overcurrent occurs.

7.The power is cut off immediately from powering condition when short circuit condition occurs.

The figure below illustrates a connection example:

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Seagate KSD-541-P manual Making PoE Connections