[asterisk-users] DTMF end '1' has duration 57 but want minimum 80 , emulating on ?IAX2/a16-q1-9657

[Steve Underwood]

On 09/21/2009 12:46 PM, Tilghman Lesher wrote:
> On Sunday 20 September 2009 22:32:41 Tzafrir Cohen wrote:
>    
>> Isn't 40ms the minimal time for a valid dtmf digit?
>>      
> $ grep -C1 'define AST_MIN_DTMF_DURATION' main/channel.c
> /*! Minimum allowed digit length - 80ms */
> #define AST_MIN_DTMF_DURATION 80
>
> This post, from the archives, is instructive and germane to the code in
> question:
> http://lists.digium.com/pipermail/asterisk-dev/2007-April/027271.html
>
>    
If a DTMF decoder doesn't register a digit in under 40ms its broken. 
80ms is the minimum total digit cycle time many people specify, 
including the silence between digits. This time varies between specs, 
though. Some things specify the minimum cycle as 100ms.

Steve