[hylafax-devel] Re: Modem Reset Commands

[Steve Williams <steve@genie96.com>]

> 
> Steve Williams <steve@genie96.com> writes:
> 
> > > - usually admins tune their modems once (e.g. adjust TX level for the
> > > specific telco line) and then store resulting settings to the NVRAM; that's
> > 
> > I have spoke on this before, but no-one that hopes to run HylaFAX RELIABLY
> > in a mixed data/fax environment can rely on this.  I know 100 % for sure that
> > I do NOT rely on the modem being in any "default" state.
> 
> :-)
> 
> Then you should never switch on your modem, because it automatically loads
> "default" ATZ profile after supplying the power.

That's fine, I just don't rely on knowing what state the modem is going to
be in when I turn it on.

I always make sure I program the modem the way I need it programmed for 
the particular thing I am using the modem for.

For example, I need to put the modem into data mode before I dial out for
a UUCP connection to a client.  I don't rely on the modem being in data
mode, I explicitly set it in my dial string at+fclass=0.  I don't rely
on result codes being on, or verbose... I set those explicitly so 
that my UUCP dialer script will work properly.

Similarily, HylaFAX has to do the same thing.  Sure, do the ATZ to reset 
the data pump, but then set all paramaters that are necessary for a fax
to be sent successfully ( or received )

If dropping dtr ( &D3 ) resets the modem to the ATZ state, then everything
still works, because I don't make ANY assumptions on what the ATZ state is.

That's all..not a big deal, we both agree fundamentally...

> 
> Look, I do not claim that ATZ has to be the only init command for all
> cases. I just propose two-step ininializing sequence (not taking into
> account that Hylafax itself does):
> 
> ModemSoftResetCmd        ATZ (default)
> ModemResetCmds           ""  (default)
> 
> You can change both parameters as you like. But for most users the proposed 
> defaults are the reasonable choice.
> 
> > I have mentioned this before..
> > 
> > HOWEVER, if the ATZ resets the data pump, then I am all for it.
> > BUT...the state of the modem after the ATZ MUST BE SUSPECT.. if a user
> > ( via cu, minicom, etc ) has set the modem to something & done an AT&W
> 
> ... then the next DTR drop will also restore NVRAM profile values (see
> Robert's message). Should DTR dropping be also prohibited? :-))
> 
> > I just like to make this real clear...  In a fax only environent, where
> > HylaFAX is the only thing accessing the modem, relying on ATZ would
> > be acceptable.
> 
> Hope to hear from you soon,
> Dmitry
> 

-- 
	Steve Williams, Calgary, Alberta, Canada
	Genie Computer Systems Inc.
	steve@genie96.com

"A man doesn't begin to attain wisdom until he recognizes that he is 
 no longer indispensable."
- Admiral Richard E. Byrd ( 1888-1957 )

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