Reach PoE4N Tester Manual 1.4
08/09/2017
Page 12
5.3.
Signature, class, and load
Full wave Bridge
and standard
overvoltage
protection
IEEE 802.3at
controller
Class options
Signature options
"detect" commands
"class" commands
Power Status
"status" command
Legacy capacitive
signature 10uF
"cap" command
Power Pair
Variable load
Max 2*660mA
"set" command
From other power pair
2 of these, one for each power pair
The IEEE 802.3at controller (also known as the PD PoE controller) used is the TI
TPS2378.
The signature resistor options are nominal, or invalid (too high). This is enough to
validate the PSE’s ability to detect the physical IEEE signature. A legacy capacitive load
can be applied which should cause the signature detect to fail. This can also be used to
simulate an AC load for AC disconnect testing. The classification (Class) loads are
standard. The "power-good" status of the IEEE controller goes active once the load
capacitor (not shown) is charged and can be monitored via the “status” command. This
command reports the status of each of the two PoE PD controllers. This will indicate
which pairs are powered.
