It is possible to prevent certain numbers from ringing your phone (AT&T landline). You will need the OBi110 in this case.
For example, if you want to block numbers 4151111111 and 4152222222 from ringing your phone, do the following settings:
1. Log in to your OBiTALK account
2. Click on your Device and go to Expert Configuration.
3. Under Physical Interfacesà Lineàline port, change inboundcallroute to {(x.4151111111|x.4152222222):},{ph}.
Note: you will need to uncheck both "OBiTALK settings" and "device default" to make changes to the parameter.
Regards,
Obihai Technology