QBZappy,
Call Forward and other calling features, such as DND, etc., are available on all trunks in the OBi device (OBiTALK, SP1, SP2, and LINE). They can be configured under the respective service's web page. OBiTALK, SP1/2, and LINE are trunks that provide voice services, while the PHONE Port and AA are consumers of these services. For the OBi devices, features such as call forward and DND are applied to incoming calls on a per trunk basis, so that they would provide the expected behavior regardless where the incoming calls are routed to (could be AA, PH, or other trunks). If SP1 or SP2 is hard-wired to ring the PH and the PH only, then you can say these call features are similar to those offered in some other ATA implementations. OBi's design is more general. Hope this is what you're looking for.