How to disable the dial tone of the DISA for outgoing call?

After several days test finally i figure out i could not use DISA with the busydetect=yes configuration, and DISA works well if i use VoIP provider to call in and call out.
Hence the problem is the server detect the dialtone as busy tone and hangup the call through Pots line.

Can anyone tell me how to disable the Dial tone of the DISA? as there is only module and i am totally lost how to modify it.