[Nut-upsuser] Debian 10 nut 2.7.4-8 and APC Back UPS 600i on 940-0020B

[tovis r-visor]

> On Sep 11, 2019, at 5:25 AM, tovis r-visor <tovis at r-visor.hu> wrote:
>>
>> I does not change any of them. Simple, after boot, using
>> $ watch upsc MYUPS
>> what is give me "LB OL"
>> from another terminal I restart:
>> # systemctl restart nut-driver.service
>> after some seconds the status is changed to simply "OL".
>
> Are there any systemd units that change the serial port settings, e.g.
> setserial? They might be changing the cable power settings (which are
> re-applied when the driver is restarted). Check the journal to see the
> order of the units at startup.
>
> Also, does your UPS support smart signaling? The APC smart protocol driver
> (apcsmart) is far more resilient than the genericups driver, IMHO. It may
> be worth buying/building a new cable, if needed, to use the smart
> protocol.
>
>

Thank you! Up to now I was looking for that. There is a suspicious
message, coming from boot screen:
[ OK ] Started controls configuration of serial ports.
Also seem to be that messages about "Network UPS tools" are after, but in
the same time, I was seen that scripts (such as rc.local) executed before
the message appear. I'm really confused with systemd start up sequences :(
I found a workaround, disabled all nut service units and put calling of
scripts to the rc.local:
systemctl start nut-monitor.service
systemctl start nut-server.service

This way the false state is gone :)
I understand, that this workaround is dangerous, especially when system is
upgraded (even safe-upgrade), failure could be detected only after reboot.
My APC Back UPS 600i is really old, from early 90's - no smart protocol,
ONLY simple signaling using (DIY) cable APC 940-0020B.

OFF: These UPS -s are really simple, they could be simply
serviced/remounted (no firmware, no mcu). Last cycle YUASA accumulator was
working almost 5 years. The trade off is the simplicity no smart
signaling, no information about accumulator healthy, no sine wave.

I still await for better solution or suggestion
  tovis