Reach PoE5 Tester Manual 1.8 03/25/2021 Page 9
3.3. UUT Connections
The RT-PoE5 has 24 test ports, configured as 12 pairs (1-2, 3-4, 5-6, etc.). Each port can
act as a PD load to the UUT. Also, each port pair can be configured to pass data from one
port to the other via internal straight-through connections, allowing the loads to be
applied while passing traffic. All data path connections are made via signal relays and
100 ohm differential pairs for data integrity.
Connect the port of the PoE supplying device under test to the UUT connector via a
standard straight-through Ethernet connector (see the Ethernet Cables section for more
information regarding cables). There is an 802.3bt class transformer isolating the UUT
ports in each port pair so that power can be tapped from the UUT (see the Data Path
section for more details).
Note that the devices connected to any given port pair cannot "see" the power from the
other port. In other words, the UUT ports in a port pair are connected from a data
perspective, and each UUT port connects to the RT-PoE5 active load from a power (PoE)
perspective.
NOTE: with high power loads, the DC balance of the patch cables used is important to
avoid DC saturation of the Ethernet transformers. DC Balance (DC resistance per side
of the power-carrying pair) should be within 3%. The standard patch cable
specifications of Cat 5, 5e, and 6 do not specify DC balance.
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