[Nut-upsdev] Re: delta protocol

Peter Selinger selinger at mathstat.dal.ca
Fri Oct 7 02:04:11 UTC 2005

Arnaud Quette wrote:
> not sure you've seen this. It might interest you:
> https://alioth.debian.org/tracker/index.php?func=detail&aid=302259&group_id=30602&atid=411544
> Arnaud
> --
> PS: I've not looked at it.

Hi Arnaud,

this is great! Someone posted a technical document on Alioth
describing a "Delta USB Report Descriptor Protocol". This document
seems to describe a serial protocol, and it also shows HID/USB usage
codes for code tables 0x0086 and 0x0085.

The HID/USB tables seem to be consistent with what we have already
partially decoded for the Belkin USB (and my guess is that it fits
Liebert as well). The serial protocol described in this document
appears to be the one from the "belkinunv" driver (which I
hand-decoded back in 2003, compare my description of it at

It seems that this document might answer some of our remaining
questions about the Belkin and Liebert protocols. I will try to
integrate this information into the newhidups driver. Perhaps there
should be a single "Delta" subdriver servicing both Belkin and

-- Peter

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