When the call arrives at the Visited MSC, the MSRN is used to determine which of the phones in this area is being called, that is the MSRN maps back to the IMSI of the original phone number dialled. The MSC pages all the mobile phone masts in the area that the IMSI is registered in order to inform the phone that there is an incoming call for it. If the subscriber answers, a speech path is created through the Visiting MSC and Gateway MSC back to the network of the person making the call, and a normal telephone call follows.