[asterisk-users] DTMF not completely muted

[Kevin P. Fleming]

Michael Smith wrote:

> When the Dahdi driver detects DTMF, it seems it's not muting the first 5-15 ms
> and sometimes the last 2-10 ms of the DTMF tone. This shows up in recorded
> voicemail greetings -- you hear a very short DTMF '#', or sometimes two blips,
> at the end of the recording.

The blip at the beginning is expected; the DTMF detector won't trigger
until it has seen a long enough continuous tone to recognize it, and
then it will begin muting the audio. The only way around this would be
to artificially delay the audio stream by 20-40ms to accommodate the
muting, but most people would not enjoy the additional latency this
would create.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
skype: kpfleming | jabber: kpfleming at digium.com
Check us out at www.digium.com & www.asterisk.org