[Nut-upsdev] Re: Serial Ports (Was Re: Common Power Management : NUT and HAL (stage 1))

[Daniel O'Connor]

On Thursday 14 September 2006 18:36, Arjen de Korte wrote:
> Maybe not. I think most (if not all) serial devices won't be harmed by
> changing the control lines (this problem is also pointed out in the serial
> PnP specification in Annex B). On the other hand, we need to be absolutely
> sure about this (or make it configurable), so at the moment I tend to
> agree not to do this automatically until we are.

I don't believe Windows does it automatically so I'm almost certain there's 
some hardware out there it will break :)

Having a "Try and detect serial device" button/option should be fine though 
IMO.

> I've had the fortune of experimenting with this configuration a few months
> ago and it poses no problems with the serial_probe program Arnaud directed
> me to a while ago (can't remember where he found it). The specification of
> the serial PnP protocol says you'll need to keep this line high for 200ms
> (if memory serves) which is not nearly long enough for the UPS to shutdown
> the load. The BackUPS Pro 650 will happily report its serial PnP string.

Ahh nice..
I am a bit cynical of APC so it wouldn't surprise me if it shut the PC down :)

> Since the serial PnP protocol is fairly old already (first draft more than
> 13 years ago) I think many (if not all) serial devices designed for the
> consumer market will at least tolerate it (serial PnP was standard from
> Windows 95 onwards if I remember correctly).

True, I guess any consumer equipment older than that has probably died 
anyway ;)

-- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
Url : http://lists.alioth.debian.org/pipermail/nut-upsdev/attachments/20060915/60f11abc/attachment-0001.pgp