[Asterisk-Users] Fax tone detection problem on bridged (PRI -> SIP) calls

[Ing. Angel Gomez]

Alex Zarubin wrote:

> Greetings,
>
> [w_pstn]
> exten => 8478106205,1,record,w_faxmsg:pcm
> exten => 8478106206,1,Dial,SIP/w_sip
> exten => fax,1,Goto(w_fax,8478106207,1)
>
> [w_fax]
> exten => 8478106207,1,Dial,Zap/g1/8478106207
>
> We send faxes (from the same fax machine) to 8478106205 and 8478106206.
>
> On 8478106205 fax tone is always detected and we have a successful fax 
> transmission to 8478106207.
> On 8478106206 call is connected to the SIP application, but the fax 
> tone is not detected, so we keep beeping (CNG) to the app.
>
> In both cases we see several sequences of 4 messages each (uncommented 
> in dsp.c) like
>         Fax energy/Second Harmonic: 57393933745.000381/22932862397.987717
> so fax_hits counter should be the same.
>
> Please, help.
>
> Alex Zarubin
> Webley Systems, Inc.
>
>
You need to give * about 3-5 seconds to recognize the CNG, so answer the 
call and then wait or background a message (silence ?) to give * time to 
recognize the CNG.

This how I received every call and is working...

Good luck.

exten => s,1,SetMusicOnHold(random)
exten => s,2,SetVar(Tries=1)
exten => s,3,Wait(1)
exten => s,4,Answer()
exten => s,5,DigitTimeout(5)
exten => s,6,ResponseTimeOut(10)
exten => s,7,BackGround(Welcome)

exten => fax,1,Dial(SIP/209||d)   <<-- Fax Device
exten => fax,2,Hangup()