[Nut-upsdev] Four UPS's via usb.

Arjen de Korte nut+devel at de-korte.org
Fri Feb 1 12:36:43 UTC 2008


> Ok, what You can suggest to me, pci serial board and serial cables or usb
> to serial converters?

Both will work with the 'megatec' driver. I have a slight preference for
the PCI serial board, because the ports the devices are connected to are
fixed. Not only logically, but also physically (by means of screws, so the
connectors can come off by accident, which is big plus for something as
vital as the connection to a UPS).

With USB serial converters this location is not quite fixed. Ie, if one of
the devices is removed

    /dev/ttyUSB0
    /dev/ttyUSB1 <- remove this one
    /dev/ttyUSB2
    /dev/ttyUSB3

chances are that on the next reboot the list will look as follows

    /dev/ttyUSB0
    /dev/ttyUSB1
    /dev/ttyUSB2

instead of

    /dev/ttyUSB0
    <missing>
    /dev/ttyUSB2
    /dev/ttyUSB3

The above should not happen, but there is no absolute guarantee it won't.
In theory, if your converters are as broken as your UPS'es (the serial
numbers must be unique according to the USB specifications), you'd risk
that the problem is still not fixed.

Best regards, Arjen
-- 
Eindhoven - The Netherlands
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