Building-Block Approach Service Creation Template Figure 13 represents what a service creation template might look like. For an outgoing call screening service, the service begins with the customer's telephone number. A four-digit extension dialing service is displayed in Figure 14 . Service logic at the SCP uses the 2111 number to determine the real telephone number of the called party. Digit Extension Dialing Service Disaster Recover Service Figure 15 illustrates a disaster recovery service.
Calls come into the switching system served by the normal location.
After triggering, communication with the SCP occurs. Based on the service logic, the call could be either routed to the normal business location or to one or more alternate business locations. This service is useful for companies or businesses that want to advertise one telephone number but want their customer's calls routed to the nearest or most convenient business location. The call is then routed to the company or business location that is closest to or most convenient for the calling party. Whenever someone calls them, the service logic determines whether the call should be routed to the Smith's telephone or an announcement should be played.