About smart dialing
With the smart-dialing feature, you can set a default country code and area code for phone numbers in the Contacts application so that you do not have to dial a country code and area code each time that you make a call, unless the country code or area code are different from the default codes that you set. Some country codes are not supported by the smart-dialing feature.
In the smart-dialing options, you can also specify the main phone number for an organization that you call frequently so that you can quickly call a contact in that organization by dialing only the extension for the contact. If you add contacts from that organization to your contact list, when you add their phone numbers, you can type only the extensions instead of typing out the main phone number for the organization.