I wouldn't suggest hacking together anything to test PoE. It's way more
complicated than it seems like it would be. If your test device said that a
link failed would you really know if it was an issue with PoE/Cabling or
your device?

If you're looking for a cheap method, here's a PoE PD client evaluation PCB
from Analog Devices
https://www.analog.com/en/design-center/evaluation-hardware-and-software/evaluation-boards-kits/DC2911A.html.
At only $95 I doubt you'd find a cheaper solution that lets you adjust the
requested power. It's not automated and it's not even in an enclosure, but
it'd give you all you need to know that PoE is working. I've haven't used
one before, so I can't say for sure if it'd work out of the box, but it
looks like it should be good.

This Fluke seems good if you want an actual tester. It tests up to 90W
802.3af/at/bt and has a 10G interface. I have no experience with it either,
but Fluke always seems to make good products.
https://www.fluke.com/en-us/product/network-cable-testers/copper/linkiq-100

Ethan Grinnell
CCIE Enterprise Infrastructure  #39723, BS CmpE
Network Engineer
Office of Information Technology, Technology Infrastructure, Networking
Portland State University


On Wed, Sep 8, 2021 at 1:03 PM Neumann, Paul <pa...@uic.edu> wrote:

> I suspect some (non-trivial) time and tinkering would be needed to make
> this work.  I see a major issue is that all the flavors (classes) of POE
> require the devices to first complete a power negotiation phase where the
> endpoint requests the proper class of power needed.  Only then is power
> delivered to your resistance (properly sized for wattage with an
> appropriate heatsink).   Also power is delivered over the data lines for
> certain poe modes - you need to separate the baseline voltage from the data
> communication that is superimposed over that.  All the above should be
> achievable for anyone with a EE background.  I’m sure there is some level
> of devil in the details.
>
>
>
> This would be a cool senior project for an  upper level/grad student in
> electrical engineering but for serious work, I would just buy a fluke
> tester.
>
>
>
> Paul
>
> --
>
> Paul Neumann
>
> Lead Network Engineer
>
>
>
> Technology Solutions (formerly ACCC)
>
> Unversity of Illinois Chicago
>
>
>
> E: pa...@uic.edu
>
> P: (312) 355-0113
>
> Room 124, Benjamin Goldberg Research Center, University of Illinois at
> Chicago
>
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>
> Visit the UIC Help Center at help.uic.edu to find IT Services, Answers,
> and Support!
>
>
>
> *From:* The EDUCAUSE Wireless Issues Community Group Listserv [mailto:
> WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU] *On Behalf Of *Beyerle, David Evan
> *Sent:* Wednesday, September 08, 2021 6:44 AM
> *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU
> *Subject:* Re: [WIRELESS-LAN] PoE Load Tester Recommendation
>
>
>
> Brad,
>
> Recall that P=V^2/R, so it seems as though applying the appropriately
> sized & load-rated resistance network across the pairs delivering power,
> and then measuring the voltage dropped across that resistance network would
> give you a reasonably good indication of whether the appropriate power is
> being delivered to the load.  For 60W in seems like you might choose R~75
> Ohm on each of two pair, but I’d encourage you to double-check my
> arithmetic.
>
> Best,
> Dave
>
> ------------------------------
>
> *From:* The EDUCAUSE Wireless Issues Community Group Listserv <
> WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU> on behalf of Floyd, Brad <
> bfl...@mail.smu.edu>
> *Sent:* Tuesday, September 7, 2021 5:43 PM
> *To:* WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU <
> WIRELESS-LAN@LISTSERV.EDUCAUSE.EDU>
> *Subject:* [WIRELESS-LAN] PoE Load Tester Recommendation
>
>
>
> Can anyone recommend a device to PoE load test network jacks? I have some
> jacks that pass the installer’s Category Certification, but are not passing
> the appropriate PoE to bring the APs online. I would like to be able to
> load test for 802.3af, 802.3at, and 802.3bt (at both 60W and 90W), as
> appropriate. I assume I would need to be able to set the load to apply (in
> Watts) and see the voltage level at the Powered Device. The usual
> constraints apply. Cheaper, but reliable is best.
>
> Thanks,
>
> Brad
>
>
>
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