[Nut-upsuser] BelkinUNV Serial Problems (Was CyberPower 1500AVRT won't load driver!)

Arjen de Korte nut+users at de-korte.org
Thu Nov 29 07:50:11 UTC 2007

> I guess you are right that we learned something from running the driver
> stand alone - but the debug level didn't seem to add as much verbosity
> as it did with other drivers. I have checked on your suggestions:

Older drivers generally are less verbose than newer ones. Over time, we
have found that adding lots of debug code (to the level of dumping all
communication between driver and UPS) will help tremendously in diagnosing
detection problems. This could be added relatively easy to the belkinunv
driver. I'll check with the maintainer of this driver.


>> Another thing could be that the serial cable used is broken.
> The serial cable was working a few days ago using the Belkin supplied
> software on another (older) linux centos 4.5 system.

That's good to know. At least we know the cable is OK and that the serial
port of the UPS is fine too. There is one thing are left that you could
check if you really want to get to the bottom of this problem. Connect
pins 2 and 3 of the serial port together (or use a loopback plug)and run a
terminal program like minicom. If you type characters, they should be
echoed back.

As a final remark, the serial port you have may not be fully RS-232
compatible with regards to the voltage levels it provides. Many UPS'es
will have optical isolators on this port that are powered by the RS-232
line. If that is not providing enough voltage and current, this may
prevent it from detecting your UPS also. If you're able to run the
belkinunv driver on your older system, this could confirm this.

Best regards, Arjen

More information about the Nut-upsuser mailing list