Why not just timeout like an auto-shutoff?  You can monitor the busy/ready 
light or a power line to the print-head, etc.

Chees,
-Neil.



On Tuesday 27 September 2005 07:23 am, Gerhard Fiedler scribbled:
> (Changed the tag to EE, since it really is EE...)
>
> Buehler, Martin wrote:
> > so i had the idea to use a pc network card with wake-up-on-lan
> > functionality to control a relais, turning on the printer.
> >
> > i have no idea if this really works, as i don't know how to connect such
> > a network card. will this work when just supplying 5v to it's wol
> > connector, or does it really have to sit in a pci slot?
> >
> > as far as i remember, calling the card's mac address rises the wol
> > signal, so this would work to control the power relais. but does the wol
> > signal stay high forever then? how can i turn the wol signal off again?
>
> I don't think there's a "shut down on LAN" command. I guess the idea is
> that after you turned the device on, it's working and you can communicate
> with it using normal network packets. So shutting it down would happen
> through some kind of network command (like remote control of a computer,
> for example). In this case of course one would need a network client at the
> location, in which case you wouldn't need WOL for your application. Maybe
> your printer has a shutdown command that can be sent over the network.
>
> I had a quick look around, and it seems that hard facts are hard to get
> by...
>
> I started with http://www.google.com/search?q=wake+on+lan+network+card+wol:
>
> - http://www.annoyances.org/exec/show/article04-101: something about
> Windows configuration to make it work, and a few discussions of problems.
> Leads to
> - http://ahh.sourceforge.net/wol/: A WOL client that sends the "magic"
> packet. Unluckily the link to the AMD site where their documentation is
> supposed to be (or was) only goes to a page that says to contact their
> sales people... :(
> - http://www.codeproject.com/useritems/WOL.asp: Here's a bit of info about
> the actual packets, plus source for another client.
> - http://www.depicus.com/wake-on-lan/what-is-wake-on-lan.aspx: Another
> description, including a network trace of a WOL packet. This article says
> that some cards need a flag to be set for WOL to work, which indicates that
> a simple solution like what you're thinking of may work with some cards and
> not with others.
>
> This all is more about the network interface than about the NIC interface.
> Maybe searching for WOL or "wake on LAN" on the IBM and AMD sites turns up
> more info. It seems that both companies claim to have invented it.
>
> OTOH, have you considered a simple remote power switch, like X-10 or so? It
> seems that for less than $40 you can get a switched outlet and a remote
> control.
>
> Gerhard


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