User Manual

Planning (hardware)
Ethernet
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PoE topologies
PoE requires a star topology. Typical PoE switches have 4 to 16 outputs.
As a result, multiple switches are used in a line topology on larger systems (e.g. suites in a hotel).
Additional topologies:
● Certain switches (general industrial types) possess an uplink, i.e. multiple switches can be switched in
series.
● An individual consumer can be powered using a PoE injector. This is an intermediate power source (mid
span), in contrast to direct power by the PoE switch (end span).
PoE switches / injectors
● Use only switched design for industrial use
● Transmission speed: 100 Mbps
● Compliant with IEEE 802.3at
● Power class 4 (12,95-25,50 W)
● Type 2
● The switches must support supply alternative A
Selection criteria
● Required number of outputs
● Required power
● Operating switch voltage
● (PoE itself operated at DC 48 V; various switches can, however, be powered for example at DC 18…24 V or
AC 230 V)
● Installation location (due to protection class)