[asterisk-users] Background / Invalid Extension through cell phone

[Jorge Mendoza]

Eric

Eric "ManxPower" Wieling wrote:
> Steve Totaro wrote:
>> Eric "ManxPower" Wieling wrote:
>>> Doug Lytle wrote:
>>>> John Congdon wrote:
>>>>> Hi,
>>>>>
>>>>> I have had an issue for a long time, and really just can't solve it.
>>>>>
>>>>> My boss and others seem to have a problem when they call into our 
>>>>> asterisk phone system.  It often takes 3-4 tries of entering an 
>>>>> extension before the system gets it right.
>>>>>
>>>>> Below is my context that the call comes into, and some debugging 
>>>>> from the asterisk console.
>>>>
>>>>
>>>> You may want to add the following to the zapata.conf
>>>>
>>>> ; If you are having trouble with DTMF detection, you can relax the 
>>>> DTMF
>>>> ; detection parameters.  Relaxing them may make the DTMF detector 
>>>> more likely
>>>> ; to have "talkoff" where DTMF is detected when it shouldn't be.
>>>> ;
>>>> ;relaxdtmf=yes
>>>
>>> I have found that relaxdtmf=yes has caused more problems than it 
>>> fixes.  In my experience problems with detecting DTMF on an FXO port 
>>> can usually be fixed by playing with rxgain and txgain.
>>>
>> What sort of problems have you seen it cause?  I guess I could see 
>> hitting the wrong extension in rare cases.  Anyways, relaxdtmf has 
>> worked wonders for me over T1s and analog lines (always seems to be 
>> cell phones that have issues, probably because of the GSM and radio 
>> distorts beyond the specs).
>
> It caused asterisk to see a single digit when two of the same digits 
> were dialed in a row.  So a user dialed 4415 and Asterisk saw 415. 
> Remember that on all cell phones (except the analog ones) DTMF from 
> the phone is sent out of band and so should not be distorted.
>
Are you sure about that?. I think that the DTMF digits are send out of 
band before the answer supervision. After that, the DTMF digits are send 
in band if they are dialled from the keypad. When I call my IVR, the 
system answer and I dial other DTMF digits, only around 20% of calls 
succeed. However if I store the DTMF sequence in the cell phone (digits, 
pause, send, digits, etc.) 100% of calls succeed.

Jorge Mendoza