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

[Eric "ManxPower" Wieling]

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.