This is by design and only the OBi200 will receive inbound calls. If you had 2 OBi2xx's, both would ring. To fix the problem you can have the OBi200 send the call to the OBi110 via the OBiTalk network. This is called forking when you send the call to multiple devices.
OBi200
Voice Services -> SP1 Service -> X_InboundCallRoute: ph,pp(200123456)
Change 200123456 to the OBi Number of the OBi110.
Use OB Expert to make this change.