Microsens MS400900M - Manual (Page 6)

24-Port PoE Injector User’s Manual Page 4/40
Introduction
Power-over-Ethernet (PoE) eliminates the need to run 100/240 VAC power to
other devices on a wired LAN. Using Power-over-Ethernet system installers need to
run only a single CAT5 Ethernet cable that carries both power and data to each
device. This allows greater flexibility in the locating of network devices and
significantly decreasing installation costs in many cases.
There are two system components in PoE – the Power Sourcing Equipment (PSE)
initiates the connection to the second component, the Powered Device (PD). The
current is transmitted over two of the four twisted pairs of wires in a Category-5
cable.
Power-over-Ethernet follows the IEEE 802.3af and is completely compatible with
existing Ethernet switches and networked devices. Because the Power Sourcing
Equipment (PSE) tests whether a networked device is PoE-capable, power is never
transmitted unless a Powered Device is at other end of the cable. It also continues
to monitor the channel. If the Powered Device does not draw a minimum current,
because it has been unplugged or physically turned off, the PSE shuts down the
power to that port. Optionally, the standard permits Powered Devices to signal to
the PSEs exactly how much power they need.
MICROSENS GmbH & Co. KG · Kueferstraße 16 · 59067 Hamm / Germany · Tel. +49 23 81/94 52-0 · FAX -100 · www.microsens.com