Feature Code Detection Leads to the Door Phone DTMF Sending Delay


  • Firmware version: 
  • Model: MyPBX-Series, TA-FXS Gateway

Problem Description

TA3200 Port 21 connects with a door phone system. And the port 21 registered as MyPBX-U510 extension. When SIP phone call to TA3200 port 21 extension number, and then press the DTMF key: **12345* will hear the door phone system IVR prompt. But the client feedback that it doesn’t work after press the **12345*, and hear a deep prompt instead of the door phone IVR prompt.


The DTMF key with “*”, it might conflict with the MyPBX feature code. And the TA3200 FXS port monitor file showing that the last one “*” delay for 9 seconds.


And the system log also showing that the last one “*” delay for 9 seconds, it was the issue.

01:56:59  *
01:57:00  *
01:57:00 1
01:57:01 2
01:57:01 3
01:57:02 4
01:57:02 5
01:57:11 *

Now we need to confirm it is a delay on MyPBX-U510 or delay on TA gateway or both delay.

From the SIP packet it shows the DTMF key delay from MyPBX-U510 to TA for 4 seconds. So we can know, TA to Port also delay too.



Customize the MyPBX-U510 and TA-3200 feature.conf file changed the feature “featuredigittimeout” from 4000ms to 2000ms which is acceptable for the user. Note that the impact would affect all feature codes timeout.

For U-Series:


For TA, you would need customize the features.conf by following this guide: User Defined Configuration Modification

The content in the custom config file is:

featuredigittimeout = 2000


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