NUT on Alix 2d2 with USB/serial adapter - dead-end?

[Criggie]

Well I have an alix 2d2 running pfsense 2.0.  This hardware has only one physical serial port, so it really needs to be left for the console, in case I need to get back into it.

So to connect an ancient APC smartUPS 620 I'm using a standard USB to Serial adapter, from Prolific Technology.  Its a PL2302 that gets used in almost everything, so its common.

The OS sees

ugen0.2: <prolific technology="" inc.="">at usbus0
uplcom0: <prolific 0="" 2="" technology="" inc.="" usb-serial="" controller,="" class="" 0,="" rev="" 1.10="" 3.00,="" addr="">on usbus0</prolific></prolific> 
```and in /dev/ there appears /dev/ttyU0

However the NUT gui does not allow me to chose /dev/ttyU0. 

So these forums suggest to directly edit /usr/local/pkg/nut.xml and replace stuff as appropriate… However this is an alix and root is mounted RO.

I have had this exact UPS working with 1.2.3 to a physical serial port in the past.

How do I go forward from here?  Abandon the console and use a hardware serial port?  Or do I edit config.xml and reupload it?  Or manually twiddle the nut.xml somehow and get it back onto the CF card?

What do you think?

[Briantist]

From the shell, mount the filesystem as RW:

/etc/rc.conf_mount_rw

To mount RO when you're done:

/etc/rc.conf_mount_ro

[Criggie]

THANK YOU BRIANIST!

Your reply is perfect, and let me mess with nut.xml to fix my problem.

For completeness, once I'd mounted the partition read/write I then edited /usr/local/pkg/nut.xml
then down in the Local Ports section I added another bit for /dev/ttyU0
                                <option><name>/dev/ttyU0</name>
                                        <value>/dev/ttyU0</value></option>
This was needed because despite being a USB tty port, it is a serial UPS and won't autodetect.

Now I can graph those details from Cacti too.

[jimp]

You should use /dev/cuaU0 for USB serial ports, not the tty device.