Re: [hylafax-users] voice prompt playback before DTMF read?

[Lee Howard <faxguy@xxxxxxxxxxxxxxxx>]

Ivan Petrov wrote:

> I am trying to implement DTMF recognition in order to better route 
> inbound faxes. So far I managed to get HylaFAX to wait and read the 
> DTMF response.
> What happens is modem picks up, waits for the DTMF entry then receives 
> the fax,  Notification email after fax is received contains CallID3 
> entry with the DTMF responce entered, which is exactly what should be 
> happening. This is great. However - if sending party does not enter 
> the necessary count of DTMF digits hylafax closes the connection 
> without receiving a fax.


Yes, I am very familiar with the situation.

> I have two questions:
>
> 1) Is it possible after specific time-out fax to be received no matter 
> DTMF has not been entered?


Yes.  (See below...)

> 2) Is it possible to playback a greeting uppon line is answered to 
> prompt sender to punch the x-digit code before submit?


Yes.

Both of these features were added to HylaFAX 4.2.3.1 (found at 
http://hylafax.sourceforge.net) and are now also available in 4.2.4.1.

The time-out part is not currently configurable (it's hard-coded at like 
10 seconds if I remember correctly), but it will automatically bypass 
DTMF detection if fax tones are heard.  In those cases the CallID for 
SHIELDED_DTMF will be whitespace for however many number of digits the 
answer-length is (i.e. "    ").

The voice part is a bit more tricky.  The man page says this about the 
new "play" command-escape-string feature:

-----------------------------------------
The "<play:C>" escape can be used to play a raw audio file with a voice 
modem.  The files are named etc/playC.raw where "C" is any character.  
This feature can be used, for example, to play a brief audio message 
after picking up the line but before answering.  A configuration example 
may be:

  ModemRingResponse:  
"AT+FCLASS=8;H1\nAT+VSM=131\nAT+VLS=1\nAT+VTX\n<waitfor:CONNECT><play:1><waitfor:OK>AT+VTS=[933,,150]"
  ModemAnswerCmd:     "<delay:100>AT+FCLASS=1;A"
  CallIDPattern:      SHIELDED_DTMF
  CallIDAnswerLength: 4

In this example using an IS-101 voice-compliant modem, a RING indication 
from the modem will cause the modem to be placed in voice mode, set ulaw 
audio compression, and via the connected phone line play back the 
etc/play1.raw audio file, which may say, "After the tone enter a 
four-digit extension, then start the fax."  Following the message a tone 
is played.
-----------------------------------------

The reason this is "tricky" is because you have to develop that 
ModemRingResponse yourself based on your modem commands per your manual 
and you have to generate that etc/play1.raw file yourself based on the 
settings used in that ModemRingResponse.

I developed that example with a MultiTech MT5634ZBA-V92, so chances are 
good that it will work for you also.  However, I'd recommend first start 
testing without the "<play:1>" part (which, when omitted, will work with 
any version of HylaFAX).  You'll not get any voice prompt, but you will 
get a "beep" tone, and that will tell you that things are working up to 
that point.

Generally, to generate the etc/playC.wav file you'd take any regular WAV 
file that you want to be your voice prompt and then you would use 
something like sox to convert it into raw digital audio, probably 
slinear, uLaw, or aLaw at 8000KHz or something.  The "format" of the raw 
audio data in that file that you use will depend on the commands you use 
in the ModemRingResponse.  In this case the governing command is 
"AT+VSM=131" which is explained by "AT+VSM=?" to be 8-bit uLaw at 
8000KHz.  So the sox command would be something like this:

 sox your_file.wav -U -b -r 8000 -c 1 play1.raw

Then you copy that play1.raw file to /var/spool/hylafax/etc/, and then 
you'd add the "<play:1>" part to the ModemAnswerCmd, restart faxgetty, 
and then try it again.

Hope this helps,

Lee.


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