[asterisk-users] DTMF detection issues

[David Matías Hernández]

Hi list,
I'm having trouble with DTFM tones detection. Usually, some tones are 
being received duplicated in Asterisk, some not. As you can imagine, 
that's a very big problem involving IVR menu options, Meetme conferences 
protected with passwords, and so on.
We are currently using DAHDi 2.2.0.2, module wct4xxp, which is managing 
a Digium TE220B card, with a hardware echo canceller attached (VPM450). 
Our service is provided by 2 ISDN E1 PRI circuits (Telefonica):


[   17.188727] Found a Wildcard: Wildcard TE220 (4th Gen)
[   17.188727] TE2XXP: Launching card: 0
[   17.188727] TE2XXP: Setting up global serial parameters
[   17.687422] About to enter spanconfig!
[   17.687422] Done with spanconfig!
[   17.687422] About to enter spanconfig!
[   17.687422] Done with spanconfig!
[   17.687422] dahdi: Registered tone zone 6 (Spain)
[   17.687422] About to enter startup!
[   17.687422] TE2XXP: Span 1 configured for CCS/HDB3/CRC4
[   17.687422] wct2xxp: Setting yellow alarm on span 1
[   17.687422] timing source auto card 0!
[   17.687422] SPAN 1: Primary Sync Source
[   17.687422] timing source auto card 0!
[   17.699422] VPM400: Not Present
[   17.719825] firmware: requesting dahdi-fw-oct6114-064.bin
[   17.731424] VPM450: echo cancellation for 64 channels
[   23.794606] VPM450: hardware DTMF disabled.
[   23.794610] VPM450: Present and operational servicing 2 span(s)

For example, when I press 0180... I get this on Asterisk (as you can 
see, number 1 is duplicated):

[Jun 17 12:39:05] VERBOSE[1935] logger.c: << [ TYPE: DTMF End (1) 
SUBCLASS: 0 (48) ] [DAHDI/6-1]
[Jun 17 12:39:06] VERBOSE[1935] logger.c: << [ TYPE: DTMF End (1) 
SUBCLASS: 1 (49) ] [DAHDI/6-1]
[Jun 17 12:39:06] VERBOSE[1935] logger.c: << [ TYPE: DTMF End (1) 
SUBCLASS: 1 (49) ] [DAHDI/6-1]
[Jun 17 12:39:07] VERBOSE[1935] logger.c: << [ TYPE: DTMF End (1) 
SUBCLASS: 8 (56) ] [DAHDI/6-1]
[Jun 17 12:39:08] VERBOSE[1935] logger.c: << [ TYPE: DTMF End (1) 
SUBCLASS: 0 (48) ] [DAHDI/6-1]

Our telco provider has told us that signalling is sent via inband mode, 
so I've messing with "toneduration", "relaxdtmf" parameters on 
chan_dahdi.conf, but I don't get better results...

As I have read in Asterisk lists the echo canceller module can be 
configured to detect DTMF tones via hardware, but it's disabled by 
default. Maybe activating it I'll get an improvement on DTMF detection? 
Or should I check other configuration choices?

Any help would be appreciated :)


Thanks in advance,

David