Faxpoll server with USR Courier V34+

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Hi,

Gerhard Ahuis wrote:
> > > > > 01/17 16:50:46 yS1  fax_wait_for: string '+IS:1,3,0,2,0,0,0,4'
> > > > This seems as if your host has lost an "F" somewhere.
> > > After I recompiled mgetty the 'F' was not lost anymore. (Can you explain?, 
> > > I can't)
> > I think this was an unique byte loss -- bad serial cable, whatever ;)
> I found the same error three times in the logfile, maybee this unique 
> byte loss occurs three times ??? .....forget about it, it doesn't matter..

Strange. Anyway, you're right, it won't harm.

> > > > > 01/17 16:51:29 ##### failed: polling failed, +FHS:-5, time=60s
> > > > -- the USR lowers the DCD line between pages, and this will lead to
> > > > "strange" errors.
> > > > 
> > > > I'm not sure, though, whether this will be sufficient to get poll
> > > > receiving to work.
> > > 
> > > When using #define FAX_SEND_IGNORE_CARRIER poll receiving is going fine. 
> > 
> > poll receiving or poll sending?
> 
> poll receiving with sendfax is going fine. (when using FAX_SEND_IGNORE 
> CARRIER).

OK, fine.

> poll sending with mgetty is going fine for only one page. The second is 
> sent into the logfile (echoed by the modem which dropped the line, maybee 
> it's the same problem as receiving a fax poll ????). 

No, this is the problem I have mentioned before. USRs *can't* do fax poll
sending, it is just broken. When I tried this, even the first page was
received partially corrupt, and then I've seen the same behaviour you see.

> > > However this option has one big disadvantage. When the connection is 
> > > broken (lost carrier), MGETTY doesn't detect it. The faxfile which is 
> >                          ^^^^^ mgetty doesn't do "poll receiving"?!?
> I'm sorry, I meant sendfax ofcourse.

OK, better :)

> > > sent, is echoed by the modem and written in the logfile..
> > 
> > FAX_SEND_IGNORE_CARRIER isn't used in mgetty. This is a bug of the USR
> > modem, it doesn't always give proper error responses upon hangup.
> > 
> > (BTW: in fax mode the connection can never be "broken" in the middle of a
> > page [unless you're using ECM which mgetty doesn't do] because fax is
> > half-duplex, the modem won't notice until the end of the page that the
> Is the carrier not monitored ?

There is no carrier to be monitored, the connection is completely
half-duplex. The sending fax does not listen to *anything* on the line
until the end of the page (when it sends "my page is finished, what do
you think about it?").

> > receiver has gone away. And *if* it notices, it *MUST* send a proper
> > +FHS:xx status code).
> > 
> > > Is it not possible to discard the carrier only when a page is completely 
> > > sent ??
> What I mean is the following: When sending a fax with sendfax, sendfax 
> monitors the carrier. When it's lost, sendfax stops sending. When using 
> FAX_SEND_IGNORE_CARRIER sendfax doesn't stop sending when the carrier is 
> lost. The fax sent, is echoed by the modem and written in the logfile.

Then your modem is even more broken than I thought.

During the page transmission (unless using ECM) the modem must *never* hang
up, and if it hangs up at the end of a page, it *must* signal this to the
host in form of some error message.

Could you send me a log file of a transmission where the modem starts
echoing the page data back to the host? In the meantime, I have a good
contact at USR support Germany, maybe he can try to get it fixed.

> Isn't it better then to discard only the carrier when a page is completely 
> sent?

Switching on and off CLOCAL while data is being sent can result in data
loss on some (not too few) broken serial drivers :( - better not fiddle
with CLOCAL more than absolutely necessary.

gert

-- 
                                                            //www.muc.de/~gert
Gert Doering - Munich, Germany                             gert@greenie.muc.de
fax: +49-89-3545980 <---new!!!              gert.doering@physik.tu-muenchen.de