If your OBi device is not used in the US, you have to at least pay attention to the ring and disconnection tone of your country PSTN standard. The following provides a very good reference such that you may modify the tones accordingly.
http://www.3amsystems.com/wireline/tone-search.htm?start=0&kCountry=38&kTone=10
YH
how i can change the tone setting in obi110 ?
eg, i live in EGYPT, what modification i have to do ??