[Asterisk-Users] GSM ISDN gateway to quadbri NT port under bristuffed Asterisk - where to set gain (I have unreliable inband dtmf recognition )?

[Leandro Morgado]

Steve Underwood wrote:

> Robert Rozman wrote:
>
>> Hi,
>>
>> I'm getting unreliable dtmf recognition (it works fine for 4-5
>> digits, errors (duplicates) on more), when transferred inband from
>> gsm gateway to NT port of quadbri under bristuffed Asterisk.....
>>
>> Since Asterisk is claimed to have good dtmf recognizer, I suspect
>> there are some settings to workarouned... I've tried dtmf relax, but
>> didn't help, so I suspect gain settings....
>>
>> Is there any other possible cause of unreliable dtmf inband
>> recognition ? Where can I set gain on voice channel (I guess majority
>> of settings under bristuff in zaptel.conf are dummy) ?
>>
>> Any other advice on this problem or similar experience ?
>>
>> Thanks in advance,
>
>
> I kind of amazed if works at all when getting DTMF out of a GSM phone.
> You really shouldn't expect it to.

We have sucessfully "read" incoming DTMF from:

a) Nokia32 Analog GSM connected to TDM400 (had to use relaxdtmf with
chan_zap)
b) Ateus BRI ISDN GSM connected to AVM Fritz (had to patch chan_capi
0.3.5 to support relaxdtmf)


Question (I'm from a software eng. background, not telco):
What would be the reason for not receiving DTMF from a GSM
phone/gateway? Do you have the time to explain why? (I'm really
interested in learning :)

Thanks,

Leandro