In order to find out the causes of the problem, you have to isolate the source of the problem.
1. Are your friend in India able to make Obitalk call to you by dialling your USA ObiNo without any failure?
2. If the answer is yes, then the Internet connection between the India and US is okay. Otherwise, there may have some problems in the Internet connection.
3. Modify the incoming route of OBi110 such that whenever every calls to your OBI110 PSTN Line, does your phone connected to the PHONE Port rings for each PSTN call without any failure?
If the answer is no, the cause of the problem is the ring detection of OBi110 is different from your India local telco.
YH