Hello, I am facing hangup delay problem using FXO (X100P) card with the following scenario: PSTN Phone--------->BTTB PSTN Gateway------->Asterisk BOX-FXO-------->SIP Endpoint When anyone make call to my Asterisk-BOX FXO, they gets IVR to press their desired SIP extension number. If calling party disconnect the his/her call before pick up the call by the called party, then called party extension rings for 40 to 45 seconds. I suspect Asterisk-BOX FXO can't detect hangup signal properly. May be there is some mis match with my selected loadzone in zaptel.conf. FYI, I tried to set different busycount value, but it doesn't work and I didn't get any difference with this. Anyway, how can I know my actual tone zone for PSTN line? I am using Asterisk in Bangladesh. I need to know BTTB tone frequencies like Dial, Congestion, Busy, Ring tone frequencies to make compatible with my FXO card. Is there any tools that I can measure my actual BTTB line's frequencies to write proper indications.conf file? I would appreciate if anyone give me any solution for the above problem. N.B. In Bangladesh BTTB is like Telco. A PSTN line provider. Regards Nahid