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

[Charles Lepple]

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.