[Nut-upsdev] serial/USB-over-HID layer for fentonups

Charles Lepple clepple at gmail.com
Wed Oct 5 13:19:24 UTC 2005

On 10/5/05, Peter Selinger <selinger at mathstat.dal.ca> wrote:
> Pierre-Yves AILLET wrote:
> > As explained on this webpage it was detected as :
> > hiddev96: USB HID v1.00 Gamepad [Ver 1.0 USB To RS232 Interface (V1.0) BaudRate
> > 2400bps] on usb-0000:00:09.0-1

note the baud rate mentioned in iProduct.

> I suspect that doing a "serial over USB" protocol is not as simple as
> that. You communicate with a serial port via IOCTLs (to set the baud
> rate, stop bits, and whatever). There are different IOCTLs for USB (to
> set an endpoint, get descriptors, and stuff like that).

Back in April when I looked at another UPS which apparently uses the
same RS232 interface chip, it appeared that the USB interface is much
simpler than what you are describing.

As best I can tell, it uses the HID protocol to organize the data into
a 64-bit buffer (well, 8 bytes, but the report descriptor says 64
bits), and energizerups reads the bits in using the Linux hiddev API.

So Unitek Alpha support may be as simple as modifying the detection
routines in energizerups.

- Charles Lepple

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