On Mon, 8 Jan 2018 20:34:17 +0000 (UTC), Kiwi User wrote:

>> I'm stumped on what to try next.
>
> A different make of USB-serial converter?

Worth a try, I had a PL2303 based convertor connected to an APC UPS.
Every so often the adpater would disconnect from the USB and
reconnect breaking the UPS Tools monitoring...

Got a FTDI FT232L based convertor and not had a sniff of the problem
since.

Curiously I still have 3 of the same PL2303 adpaters in use with
other devices without a hitch. Yes, I did try some of those with the
UPS and they also failed in the same way.

--
Cheers
Dave.

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