You aren't very specific with your question. The OBi doesn't really forward calls, it can bridge a call. You can use a provider to bridge a call to another number. When you do this, the person receiving the call will not see the inbound callerid. They will see the callerid of your provider. The only way to preserve the callerid is to bridge the call to a SIP client, like a softphone installed on an Android.
To unconditionally bridge a call using SP1:
Voice Services -> SP1 Service -> CallForwardUnconditionalEnable: Checked
Voice Services -> SP1 Service -> CallForwardUnconditionalNumber: sp1(18005551212)
There are options for OnBusy and OnNoAnswer.
