Modem gives error

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Hi,

meunier@idiom.com wrote:
> In article <m0xDaZi-0000kAC@mobile.greenie.muc.de>
> gert@greenie.muc.de writes:
> 
> >It's one of the new "all shiny outside and crap inside" Rockwell modems,
> >which doesn't have any usable fax interface anymore :-(
> 
> Well, as the proud owner of one of those new "all shiny outside and
> crap inside" Rockwell modems, I take offense at your use of the word
> "usable". See below.
> 
> >The Class 1 fax interface is not supported by mgetty, but you might want
> >to give "efax" or "hylafax" a try. (Class 1 timing is very difficult to
> >do on a loaded unix system, but both programs work well on a lightly loaded
> >machine with only one modem).
> 
> I have a lightly-loaded Linux box, and efax works just fine with my
> Class 1 Rockwell-inside modem. So, this modem is as "usable" as any
> for me.

Well, you're just an amateur, I'd say.

In the professional world, "one modem on a lightly loaded machine works
just fine" ist just not enough. I have one server here that runs 16 class
2 modems at the same time, and it's only a poor 486. All modems run
absolutely reliable, even if the machine has high load.

*This* is what we want. And this is not possible with class 1.

> And just for kicks, I took a peek at the efax code for handling Class 1
> modems, and it looks fairly straightforward. So, anyone out there up for
> hacking mgetty so that it, too, can handle Class 1? I'd do it myself,
> but I just don't have the cycles right now.

Class 1 is not that hard, but it requires some very strict timing, which
you can't guarantee on (normal) unix systems. If you miss that timing,
faxing will get very unreliable.

This is why I decided to not include class 1 support in mgetty. Mgetty's
primary design goal is "reliability". And you can't have very good
reliability with class 1 modems, except on a real-time capable operating
system, like QNX or similar beasts.

> efax is able to spawn getty if it detects an other-than-fax call, as
> long as getty realizes that the modem is already off-hook. 

This is right the next problem: with class 2/2.0, there is a well-defined
interface for the modem to distinguish between fax and data. With class
1, it's not possible to distinguish between these call types, because the
standard command set doesn't have the necessary commands and responses.
*Some* modems have added extra status responses for it, but that's
strictly non-standard.

> Can vgetty
> be invoked in this way? I'd like to have efax running as a daemon, and
> have it spawn vgetty to catch voice/data calls. Will this require a hack
> of vgetty to get it to work?

Yes.

> The cleanest solution in my book is to have mgetty support Class 1.
> Anyone out there willing to take this on?

No. You don't know what can of worms you're opening.

gert
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Gert Doering - Munich, Germany      gert@greenie.muc.de
fax: +49-89-3545980     gert.doering@physik.tu-muenchen.de
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