Nut upsuser - Jan 2015 - R: NUT and relay on USB

So, just as recap:
I connect USB A (female) to USB B (male) adapter -> HUB -> 2 USB wires
male
to male,  one to raspberry and another one to my device.

Thanks a lot.
I hope that it works fine :)

Maurizio 

-----Messaggio originale-----
Da: Charles Lepple [mailto:clepple at gmail.com] 
Inviato: marted? 20 gennaio 2015 13:38
A: Maurizio
Cc: NUT List
Oggetto: Re: [Nut-upsuser] NUT and relay on USB

On Jan 20, 2015, at 4:39 AM, Maurizio <maurizio.iacaruso at gmail.com>
wrote:
> Hi there,
> I have a question about a raspberry pi as NUT server and a
"relay".
> I explain my situation: I have an UPS with USB port, so I connect it 
> to the rasp. The problem is that I have a device manageable only via 
> USB port.
> How can I handle this configuration?
> My assumptions are:
> 1) split the USB cable from UPS to rasp and device, but I don't know 
> if it works
As Manuel mentioned, you will need a USB hub. It will work better with an
external power supply for the hub.

However, if you don't already have a hub, you may want to consider a
Raspberry Pi Model B or B+, with 2 or 4 ports, respectively.
> 2) connect the UPS to rasp directly, so connect the rasp (by GPIO) to 
> device as a Serial port with a DIY cable.
> 
> The problem with second solution is that I don't know if (and how) I 
> can do it with NUT.
> 
I don't think anyone has tried connecting to the serial port on the RPi
expansion header, but NUT should not have a problem (as long as the driver
is not expecting flow control pins). However, the serial port is TTL levels,
so you would need a TTL-to-RS-232 level shifter chip. The USB hub would be a
lot simpler, IMHO. 

--
Charles Lepple
clepple at gmail

On Jan 20, 2015, at 7:43 AM, Maurizio Iacaruso <maurizio.iacaruso at
gmail.com> wrote:
> I connect USB A (female) to USB B (male) adapter -> HUB -> 2 USB
wires male
> to male,  one to raspberry and another one to my device.
I'm not sure I understand your setup.

This should work, using standard USB cables:

 <- upstream       downstream ->
     <- host       device ->

            A->B   A->B

Raspberry Pi -> hub -> UPS
                 |
                 \---> device

The problem is that there is no equivalent of a "crossover cable" or
"null-model adapter" for USB. (I am ignoring USB OTG for the moment,
since you want the RPi to talk to the UPS). There are many USB adapter cables
out there that will only work for supplying power, or only with point-to-point
USB OTG.

-- 
Charles Lepple
clepple at gmail



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Setup that I was on mind is a little different, but I think your setup works
well.

In my setup the HUB is connected directly to the UPS, then the cables go to
raspberry and device.

In your setup the HUB is connected directly to the raspberry, then the
cables go to UPS and Device.

 

It?s Ok?

 

In both configurations I need the same things: Male B->female A adaptor, HUB
and 2 male A-> male A cables. 

The male A- male A cables have any peculiarity? Can I buy it or make it
myself without problems? 

 

Thanks a lot for advice. 

 

 

 

Da: Charles Lepple [mailto:clepple at gmail.com] 
Inviato: marted? 20 gennaio 2015 14:23
A: Maurizio Iacaruso
Cc: NUT List
Oggetto: Re: [Nut-upsuser] R: NUT and relay on USB

 

On Jan 20, 2015, at 7:43 AM, Maurizio Iacaruso <maurizio.iacaruso at
gmail.com
<mailto:maurizio.iacaruso at gmail.com> > wrote:




I connect USB A (female) to USB B (male) adapter -> HUB -> 2 USB wires
male
to male,  one to raspberry and another one to my device.

 

I'm not sure I understand your setup.

 

This should work, using standard USB cables:

 

 <- upstream       downstream ->

     <- host       device ->

 

            A->B   A->B

 

Raspberry Pi -> hub -> UPS

                 |

                 \---> device

 

The problem is that there is no equivalent of a "crossover cable" or
"null-model adapter" for USB. (I am ignoring USB OTG
<http://en.wikipedia.org/wiki/USB_On-The-Go>  for the moment, since you
want
the RPi to talk to the UPS). There are many USB adapter cables out there
that will only work for supplying power, or only with point-to-point USB
OTG.

 

-- 
Charles Lepple
clepple at gmail



 

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