Re: [hylafax-users] multitech modem dropping DTMF digit

[Christopher <chrismcc@xxxxxxxxxxxxxxxx>]

Hello...


On Tue, 2010-03-23 at 21:48 -0700, Lee Howard wrote:
> Christopher wrote:
> > minicom output:
> > 1: info
> > OK                                                                              
> > ATI                                                                             
> > MT5656ZDXV                                                                      
> >                                                                                 
> > OK                                                                              
> > AT
> > +FCLASS=?                                                                     
> > 0,1,1.0,2,8,10                 
> >
> >
> > 2: Broken DTMF via minicom
> > RING                                                                            
> > AT+FCLASS=8;
> > +VLS=1                                                              
> > OK                                                                              
> > ./.4.9.~./.8.~
> >
> >
> > 3: Good DTMF from other modem
> > RING                                                                         
> > AT+FCLASS=8;
> > +VLS=1                                                           
> > OK                                      
> > ./.4.~./.9.~./.8.~     
> >   
> 
> This latter one is how it should be, marked with / and ~.  The "broken" 
> version is missing some markers.  This is a bug in the modem.  But 
> HylaFAX could be made to cope with it in this particular case.  (See the 
> attached patch).
> 

This is actually good to hear.  If the problem had been on the cisco
side, I suspect things would be more difficult.  Unfortunately this
modem is brand new and already has the latest firmware.


> In the IS-101 specification there is a provision whereby the modem can 
> inform the DTE (software) how long the DTMF was present.  It does this 
> by repeating the DLE+digit within the / and ~ markers.
> 
> In this particular case HylaFAX could be made to cope because the 
> "repeated" digit is not the same.  It changes from 4 to 9, and so it's 
> easy to see the modem's mistake here.
> 
> However, if the DTMF digits had been 448 instead, and if the same error 
> happened, then there's no way to know if the modem was trying to say 
> that it heard one 4 and one 8, but that the 4 was present for twice as 
> long as the 8.
> 
> I don't know if that makes sense.
> 

yes it does make sense.  Unfortunately, my production range is from
600-899.   Sending a fax that was destined for HR or Finance to someone
else, "would be bad".



> So the untested patch (attached) will work fine as long as the DTMF 
> digits are different from each other.  If the DTMF digits are "444" then 
> it won't do much good.
> 

I'll give it a shot to verify your code in case someone needs it in the
future.  I'm going to steal a modem from a different (non fax) server
and try it.


> Thanks,
> 
> Lee.
> 

Thank you!



-- 
Christopher McCrory
 "The guy that keeps the servers running"
 
chrismcc@xxxxxxxxxxxxxxxx
 http://www.pricegrabber.com
 
Let's face it, there's no Hollow Earth, no robots, and
no 'mute rays.' And even if there were, waxed paper is
no defense.  I tried it.  Only tinfoil works.



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