[asterisk-users] Double DTMF digits sent on IAX native bridge

[Remi Quezada]

Hi,

I have two asterisk servers one is connected to the PSTN and the other
one is connected to SIP users.  The two servers connect with each other
using IAX.  When I have an incoming call from PSTN to the asterisk
servers and have a forward to go back out to the PSTN the two IAX
channel bridge together.  Now every time I dial a DTMF digit, the
asterisk is sending two DTMF digits.  I enable debugging for iax and I
do see it sending the DTMF digits two times.  Here is what I see:


Rx-Frame Retry[ No] -- OSeqno: 022 ISeqno: 019 Type: IAX     Subclass:
ACK   
   Timestamp: 50018ms  SCall: 00004  DCall: 16385 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 018 ISeqno: 021 Type: DTMF    Subclass: 1
   Timestamp: 51523ms  SCall: 00003  DCall: 00002 [192.168.15.201:4569]
Tx-Frame Retry[-01] -- OSeqno: 021 ISeqno: 019 Type: IAX     Subclass:
ACK   
   Timestamp: 51523ms  SCall: 00002  DCall: 00003 [192.168.15.201:4569]
Tx-Frame Retry[000] -- OSeqno: 019 ISeqno: 022 Type: DTMF    Subclass: 1
   Timestamp: 51543ms  SCall: 16385  DCall: 00004 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 022 ISeqno: 020 Type: IAX     Subclass:
ACK   
   Timestamp: 51543ms  SCall: 00004  DCall: 16385 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 019 ISeqno: 021 Type: DTMF    Subclass: 2
   Timestamp: 52083ms  SCall: 00003  DCall: 00002 [192.168.15.201:4569]
Tx-Frame Retry[-01] -- OSeqno: 021 ISeqno: 020 Type: IAX     Subclass:
ACK   
   Timestamp: 52083ms  SCall: 00002  DCall: 00003 [192.168.15.201:4569]
Tx-Frame Retry[000] -- OSeqno: 020 ISeqno: 022 Type: DTMF    Subclass: 2
   Timestamp: 52103ms  SCall: 16385  DCall: 00004 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 022 ISeqno: 021 Type: IAX     Subclass:
ACK   
   Timestamp: 52103ms  SCall: 00004  DCall: 16385 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 020 ISeqno: 021 Type: DTMF    Subclass: 3
   Timestamp: 52663ms  SCall: 00003  DCall: 00002 [192.168.15.201:4569]
Tx-Frame Retry[-01] -- OSeqno: 021 ISeqno: 021 Type: IAX     Subclass:
ACK   
   Timestamp: 52663ms  SCall: 00002  DCall: 00003 [192.168.15.201:4569]
Tx-Frame Retry[000] -- OSeqno: 021 ISeqno: 022 Type: DTMF    Subclass: 3
   Timestamp: 52683ms  SCall: 16385  DCall: 00004 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 022 ISeqno: 022 Type: IAX     Subclass:
ACK   
   Timestamp: 52683ms  SCall: 00004  DCall: 16385 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 021 ISeqno: 021 Type: DTMF    Subclass: 4
   Timestamp: 53223ms  SCall: 00003  DCall: 00002 [192.168.15.201:4569]
Tx-Frame Retry[-01] -- OSeqno: 021 ISeqno: 022 Type: IAX     Subclass:
ACK   
   Timestamp: 53223ms  SCall: 00002  DCall: 00003 [192.168.15.201:4569]
Tx-Frame Retry[000] -- OSeqno: 022 ISeqno: 022 Type: DTMF    Subclass: 4
   Timestamp: 53243ms  SCall: 16385  DCall: 00004 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 022 ISeqno: 023 Type: IAX     Subclass:
ACK   
   Timestamp: 53243ms  SCall: 00004  DCall: 16385 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 022 ISeqno: 021 Type: DTMF    Subclass: 5
   Timestamp: 53703ms  SCall: 00003  DCall: 00002 [192.168.15.201:4569]
Tx-Frame Retry[-01] -- OSeqno: 021 ISeqno: 023 Type: IAX     Subclass:
ACK   
   Timestamp: 53703ms  SCall: 00002  DCall: 00003 [192.168.15.201:4569]
Tx-Frame Retry[000] -- OSeqno: 023 ISeqno: 022 Type: DTMF    Subclass: 5
   Timestamp: 53723ms  SCall: 16385  DCall: 00004 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 022 ISeqno: 024 Type: IAX     Subclass:
ACK   
   Timestamp: 53723ms  SCall: 00004  DCall: 16385 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 023 ISeqno: 021 Type: DTMF    Subclass: 6
   Timestamp: 54163ms  SCall: 00003  DCall: 00002 [192.168.15.201:4569]
Tx-Frame Retry[-01] -- OSeqno: 021 ISeqno: 024 Type: IAX     Subclass:
ACK   
   Timestamp: 54163ms  SCall: 00002  DCall: 00003 [192.168.15.201:4569]
Tx-Frame Retry[000] -- OSeqno: 024 ISeqno: 022 Type: DTMF    Subclass: 6
   Timestamp: 54183ms  SCall: 16385  DCall: 00004 [192.168.15.201:4569]
Rx-Frame Retry[ No] -- OSeqno: 022 ISeqno: 025 Type: IAX     Subclass:
ACK   
   Timestamp: 54183ms  SCall: 00004  DCall: 16385 [192.168.15.201:4569]

Any ideas on how I can fix this so it only detects one?  I've tried
relaxing the DTMF detect, but that didn't seem to work.  This is only
happening when the two IAX channel bridge together.  If I have a call
terminating to a SIP user or the PSTN and dial any digit it detects it
only once.   I verified this by turning on iax debugging also. 

Thanks

Remi