To pass caller ID when forwarding with an OBi, you need to use a provider that allows you to supply caller ID in the From header. AFAIK, there are no free ones. Possibilities include Voxbeam, FlowRoute and maybe CallWithUs. What provider do you have on SP1? On SP2? What is cost, if any, to call your mobile from your landline? What are the first 3 digits of your mobile number (after the 972)? (I am assuming that this is the same OBi, in Israel, mentioned in your other post. If not, what country is it in and who is your cell carrier?)