Standard for Ethernet power-sourcing equipment

Edited by the Manufacturingtalk editorial team May 17, 2006

PoE, or IEEE 802.3af, has been standardised since 1999 to define a way to build Ethernet power-sourcing equipment and powered terminals.

PoE, or IEEE 802.3af, has been standardised since 1999 to define a way to build Ethernet power-sourcing equipment and powered terminals.

The specification involves delivering 48 volts of DC power over unshielded twisted-pair wiring.

With the rapid growing number of network devices in industries, wiring DC connections for each of them is a costly task.

The 802.3af standard removes the need for additional outlets and the labour cost incurred from contracting electricians to install them and make the Ethernet RJ-45 plug and socket the first universal worldwide power connectors.

The current delivering to each node by PoE is limited to 350 milliamps and the total amount of continuous power, considering power loss over the cable run, is 12.95 watts per node.

Most network devices typically consume 3.5 to 10 watts.

Moreover, since PoE technology supporting a point-to-multipoint power distribution architecture, parallel to the data network, network managers can use a single UPS at the network core to back up multiple scattered devices on the LAN.

802.3af defines two types of power source equipment: end-point and mid-span.

End-point refers to an Ethernet switch with embedded Power over Ethernet technology.

Mid-span devices resemble patch panels and are placed between legacy switches and the powered devices.

Each of the mid-span ports has an RJ-45 data input and data/power RJ-45 output connector.

Korenix JetNet 3705 is a industry-grade 802.3af End-point Switch with 4 PoE ports, each of which deliver full 15.4W power, and one uplink 100Base-Tx or 100Base-FX single-mode/multi-mode fiber port.

Not like commercial switches, Korenix JetNet 3705 has IP30 grade mechanical design that can be put not only in air-conditioned offices, but in outdoor or industrial harsh environment.

The port event alarm and diagnostic LED gives clear indication of the switch port status.

JetNet 3705 best fitted for IP surveillance in campus, community, banking, and traffic system.