1. Yes, quite simple. Change to this in your OBi110:
Physical Interfaces > LINE Port > InboundCallRoute:
{ph,pp(ob500123456)}
Where 500123456 is your OBi202 number. This will ring the phone attached to the OBi110 and the OBi202 at the same time. You can delay the incoming call from ringing the OBi202 if required:
Physical Interfaces > LINE Port > InboundCallRoute:
{ph,pp(ob500123456;d=10)}
This delays the forwarding by ten seconds.
2. Yes, but you need a SIP provider set up on the OBi110 to use to forward the calls. It's the same type of setup. Say you have a SIP provider on sp1 in the OBI110:
Physical Interfaces > LINE Port > InboundCallRoute:
{ph,sp1(12345678901)}
Where 12345678901 is the DID that is registered on the OBi202.
The only catch to watch out for with Method 1 is if the OBi110 and OBi202 are in the same account. If so, then OBiTALK automatically puts them in each others' Circle of Trust and the forwarded call may get directed to the OBi202's Automatic Attendant. To stop that behaviour simply change the OBi202 Voice Services > OBiTALK Service > InboundCallRoute back to its default setting of "ph".