[Nut-upsuser] Extracting shutdown command from "sniffed" USB traffic

[Erik De Boeck]

Hi all,

In light of issue #2666 (
https://github.com/networkupstools/nut/issues/2666#issue-2623441838), I
"sniffed" USB traffic from APC's `PowerChute Serial Shutdown` software
(with the help of this guide (https://www.youtube.com/watch?v=0MC-D_oNzbk)).
I hope to be able to find out the shutdown command for my APC "Back-UPS
BX750MI FW:295202G -302202G". APC's `PowerChute Serial Shutdown` software
is able to shut the UPS down, so there must be a command, is my reasoning.

*Any help on figuring this command out from the pcap files, is welcome!* I
haven't got the slightest idea on how to go about it...

I was able to generate two logs. The scenario was both initially the same:
I unplugged the UPS from the electricity grid, and the `PowerChute Serial
Shutdown` software started closing down my (Windows) laptop. Then I tried
two scenarios:

- `2024-11-14-APC-BX750MI-1.pcap`: I let everything run its course, and the
UPS shut down, a little over a minute after my laptop had shut down
completely (so maybe two minutes after initiating the process, as
referenced on that forum I linked somewhere above?). I then plugged the UPS
back in, and it restarted (of course).
- `2024-11-14-APC-BX750MI-2.pcap`: As soon as Windows notified me of the
shutdown that was going to occur, I plugged the UPS back in. I was
pleasantly surprised that the same process as in scenario 1 happened, and
the UPS power cycled.

The only caveat is of course that I don't know whether the `PowerChute
Serial Shutdown` software shut down `USBPcap` prior to giving its final
command - the holy grail - to the UPS... I don't think this is the case: I
saw `2024-11-14-APC-BX750MI-2.pcap` "growing" even after I plugged the UPS
back in.

(Uploading files to a mail link is probably useless, so here's a link to a
directory on my Google Drive, where they can be found:
https://drive.google.com/drive/folders/12xLZH4YWJGXEjNETs2YBJix4boIUVDAE?usp=sharing
.)

Thanks in advance to any and all! ;)

Kind regards,

Erik
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